Introduction

Extremism exists in many forms, including race, politics, ideology, organization and religion. Religious extremism, in particular, has been present for many years, predating other forms of extremism. However, it remains a significant problem in the world today, exacerbated by technological advancements (Pratt 2010; Wibisono et al. 2019). The root causes of violence and terrorism often intersect with religious extremism, leading to perceptions of extremist groups. Moreover, the rise of extremism has been associated with a decline in moderation and an increase in injustice, particularly in Muslim-majority countries (Hanif et al. 2021; Kartini et al. 2019). The term “religious extremism” often carries negative connotations and may unjustly stereotype certain religious groups (Ismail and Mujani 2023; Wibisono et al. 2019). For instance, following the events of 9/11, there was a surge in public fears in the USA, leading to increased anti-Muslim bias in media reporting associating Islam with extremist movements (Ismail 2022; Schanzer et al. 2010; Smith and Zeigler 2017).

Extremism is broadly defined as holding radical views that departs from societal norms and has been linked to negative outcomes such as prejudice, hostility and armed conflict (Altemeyer and Hunsberger 1992; Cornell 2005; Koopmans 2015). Within this spectrum, religious extremism is a subset where religious ideologies serve as a driving force behind extreme actions. Both extremism and religious extremism share common features such as the rejection of moderation and a tendency for conflict. Recognizing the interconnections, both extremism and religious extremism often conflated with the term “terrorism” in certain contexts, leading to misunderstandings (Smith and Zeigler 2017; Wibisono et al. 2019). Literature on extremism and religious extremism presents various views and definitions, lacking a universal standard (Pauwels and Hardyns 2018; Rahman 2018; Dawson 2019; Asal et al. 2020; Bidova et al. 2020; Breidlid 2021; Akhmetova et al. 2021; Riedel 2021; Abdellatif 2022; al-Slaihat 2023; Saada 2023).

To analyse the multidimensional definitions and views of extremism and religious extremism, this paper presents a systematic taxonomy of the topics to enhance insights and establish indicators for better understanding. This review process aims to contribute to the standard definition of extremism and religious extremism. Given the evolving nature of extremism in the modern world, it is essential to explore accurate and standardized definitions by considering various perspectives from scholars, governments, and agencies. Besides, focusing solely on religious extremism would neglect the broader context of extremism, for instances, social and economic injustices, identity politics and perceived marginalization are drivers common to all forms of extremism (Hanif et al. 2021). Religious extremism often amplifies these factors through ideologically charged narratives, making it critical to examine both dimensions together.

Building upon this background, the primary research contributions of this paper are twofold. Firstly, it offers a systematic literature review (SLR) and taxonomy of the standard definition of extremism and religious extremism, categorizing literature into two main taxonomies to present multiple perspectives. Secondly, it aims to establish a standardized definition of extremism and religious extremism as a baseline contribution to the research topic. The remainder of this paper is structured as follows: the subsequent section outlines the research methodology, including systematic review design, identification, screening and eligibility criteria. Following that, the third section elaborates on the results and discussions of the systematic literature review (SLR). Lastly, the fourth section provides limitations, future directions and concluding remarks.

Materials and Methods

Systematic review design

The review process was conducted using an established systematic review technique, which follows a framework proposed by Research Methods & Reporting (PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews), accompanied by a checklist of 27 items to guide the reporting of systematic reviews (Page et al. 2021). The checklist was specifically designed to ensure that systematic reviews are reported comprehensively and accurately, with detailed reporting of each process that will enhance the reproducibility of research and providing clear methodology for others to follow (Belle & Zhao 2023). It is crucial to get transparent for building upon existing research and ensuring the meaningful contribution to the knowledge in a given area (Sarkis-Onofre et al. 2021; Sohrabi et al. 2021; van den Akker et al. 2023). Additionally, guidance was sought from the Joanna Briggs Institute (JBI), which is informed by the updated methodology of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMAScR) (Peters et al. 2015, 2020; Tawfik et al. 2019). The study has been registered on the Open Science Framework (OSF) with the registration https://doi.org/10.17605/OSF.IO/JVC3P. This review approach is critical in addressing the challenges researchers face in placing and analysing relevant studies, as it promotes a systematic and unbiased synthesis of the literature (Johnson & Phillips, 2018; Ioannidis 2016).

The research question for this systematic literature review (SLR) has been developed using the SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research Type) framework (Cooke et al. 2012). It serves as a comprehensive tool for guiding the design and evaluation of research studies across various methodologies, including qualitative, quantitative or mixed methods approaches to identify essential aspects or elements that should be included in the SLR’s research question. Each component of the framework plays a crucial role in ensuring methodological rigour and coherence throughout the research process. Firstly, the Sample component entails the careful selection of participants or cases, employing purposive or random sampling techniques depending on the research type. Secondly, the Phenomenon of Interest directs attention to the central topic under investigation, emphasizing the nuanced exploration of subjective experiences or quantitative variables. Thirdly, the Design component outlines the methodological approach, encompassing data collection methods and analysis techniques tailored to the chosen research paradigm. Fourthly, Evaluation criteria are established to assess the trustworthiness, validity and reliability of findings, fostering confidence in the research outcomes. Lastly, the Research Type delineates the overarching methodology employed, whether qualitative, quantitative or a combination thereof, ensuring clarity and coherence in research design and execution. Through meticulous consideration of these components, researchers can effectively navigate the complexities of their chosen research methodologies, ultimately enhancing the quality and integrity of their study outcomes. This study employed the components as followed: Scholars/agencies (Sample), definition of extremism and religious extremism (Phenomenon of Interest), methodology approach (Design), views related to the extremism definition (Evaluation) and qualitative, quantitative or mix method (Research Type) as the basis for formulating the primary research question for this SLR, which is:

  1. i.

    What are the views or definitions stated by the scholars regarding extremism and religious extremism?

Identification

Identification is a process to recognize and diversify appropriate keywords for use in the article or reference search process for the systematic literature review (SLR). Keywords are necessary in the search process and can enhance the accuracy of the articles/references obtained for referencing in the SLR. Based on the research question stated earlier, three main keywords have been selected: the use of “definition”, “extremism”, “religious extremism” and “point of view” or “perspective”. To diversify the keywords that can be used, synonyms, related words and variations of the main keywords have been sought. This search effort was conducted through online thesauruses, referencing previous research keywords, and using the WoS and Scopus database. The results of this search strings process can be referred to in Table 1.

Table 1 The Search Strings.
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Based on the selected keywords, the process of searching for articles/references has been conducted in two main databases, namely Web of Science and Scopus. Both of databases were chosen based on their respective advantages. Firstly, according to a study by Gusenbauer and Haddaway (2020), databases like Web of Science and Scopus have strengths in comprehensive searching, more stable search results and more advanced search functions compared to other databases. Martín-Martín et al. (2018) also highlighted the advantages of Web of Science and Scopus in terms of quality control and systematic indexing.

The search methodology employed in retrieving articles and references from the databases Web of Science and Scopus involved advanced searching techniques, incorporating fundamental functions such as Boolean Operators (e.g., AND, OR), phrase searching, truncation, wild cards, and field codes functionality, as delineated in Table 1. Leveraging a strategic selection of keywords, databases and search techniques, the exhaustive search yielded a combined total of 269 articles from Scopus and 241 articles from Web of Science. Each of these articles will undergo subsequent screening, constituting the second stage within the systematic search strategy.

Screening

A total of 510 articles successfully obtained in the identification process will undergo the screening process. Screening is a process in which inclusion criteria are established and used to select articles suitable for the systematic literature review (SLR) being conducted (Shaffril et al. 2020). The first criterion used in this SLR is the year of publication, where publications within the last five years (2018 to 2023) have been chosen. The selection of this timeframe is justified by several reasons. Firstly, it aligns with the concept of study maturity discussed by Kraus et al. (2020), wherein many relevant articles have been obtained during this period. Additionally, extremism was kept changing and adapt to the new era and it was better to get the latest articles for the review.

Furthermore, to control quality, this SLR only includes publications in the form of journal articles and review articles with complete data, to avoid confusion in reading and understanding, only articles published in English is selected. Moreover, only articles with relevant empirical data can be included in the SLR, as the main objective of this SLR is to identify and analyse findings from past studies rather than review them.

Another inclusion criterion is the focus of the findings. The selected articles must have findings focused on the definition of extremism and religious extremism. If an article mentions that their study investigates extremism but does not clearly state about definition or the perspective of scholars about extremism and religious extremism, then that article will be excluded. This is essential to ensure that all selected articles can offer findings relevant to the SLR being conducted (Refer Table 2). After completing the screening process, a total of 485 articles were excluded for not meeting the established criteria, leaving 25 articles available for the next stage.

Table 2 Inclusion Criteria.
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Eligibility

All the selected articles will undergo a second screening process, known as eligibility. Eligibility is conducted to ensure that all the chosen articles are genuinely relevant and can be used in this systematic literature review (SLR). This process is carried out by referring to the titles and abstracts of the selected articles. If it is still uncertain whether the selected articles are relevant after reading the title and abstract of the study, then the methodology, results and discussion sections of the article will be referred to. During this process, a total of 9 articles out of 25 were excluded due to their lack of focus on the research question. Based on this process, 16 articles have been chosen to proceed to the next stage, which is article quality assessment (Fig. 1).

Fig. 1: Flowchart of the systematic search process.
figure 1

This figure outlines the systematic search process for identifying studies via databases. It includes the identification, screening, eligibility assessment and final selection of literature used for analysis. The flowchart depicted the number of records identified, screened, excluded and included at each stage of the process.

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Articles quality assessment

The critical process of conducting a quality assessment on the selected articles and references is essential for mitigating biases and identifying any articles that may deviate from the study’s focus or lack rigorous methodology. Evaluators, chosen from among the researchers involved in the study, undertook this task diligently. Given the diverse range of study designs encompassed in the literature—ranging from quantitative and qualitative to mixed methods—evaluators leveraged the Mixed Methods Appraisal Tools (MMAT) to facilitate the evaluation process (Hong et al. 2018). In accordance with the study designs utilized in the articles and references, a comprehensive set of evaluation criteria was employed, comprising two fundamental criteria and five specific criteria. Initially, the two basic criteria were applied to assess the quality of articles: firstly, determining whether the research questions were clearly delineated, and secondly, evaluating whether the acquired data sufficiently addressed the research questions. Articles meeting these foundational criteria proceeded to the subsequent phase, where they were categorized based on study design—whether qualitative, quantitative, or mixed methods. Following this initial assessment, the remaining articles underwent evaluation based on five specific criteria to further ascertain their quality and suitability for inclusion in the study.

Evaluators employed a binary assessment approach (Yes/No) for each criterion, with an option for ‘Cannot tell’ in cases of uncertainty. Consensus between evaluators was required for each evaluation, with a third opinion sought in cases of disagreement. Only articles meeting at least three of the five criteria based on the study design questions were deemed of sufficient quality for inclusion in the systematic literature review (SLR). Out of the 16 articles evaluated, 11 met the inclusion criteria, while five articles—those by Scott and Shanahan (2018), Yusof et al. (2019), Groppi (2020), Jian et al. (2020) and Ushama (2022) were excluded due to mismatches with study criteria under the selection based on the study design either qualitative, quantitative or mix-method research. All of the five excluded articles were under the qualitative research design and did not meet at least three of the five qualitative criteria (see Table 3).

Table 3 Selection of Basic Study Criteria.
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Scott and Shanahan (2018) and Groppi (2020) were excluded for not meeting several criteria, including deriving findings inadequately from the data, failing to substantiate result interpretations with sufficient evidence and lacking coherence across data sources. Similar to Yusof et al. (2019) did not satisfy essential requirements such as employing qualitative data collection insufficiently aligned with the research question, inadequately deriving findings from the data and unable to ensure coherence in the interpretation of results. Jian et al. (2020) and Ushama (2022) were rejected due to a comprehensive failure to meet all evaluation standards, which included an inappropriate qualitative approach for the research question, poorly derived findings, inadequate data collection, insufficiently supported result interpretations and inconsistency across qualitative data processes. The exclusions highlighted critical measure to adequately assess every article to be included in the systematic reviews that follows accurately the research questions of the studies.

Data extraction and analysis

The subsequent phase of the study involved the extraction of data from the selected articles, a task undertaken by two researchers. This process of data extraction concentrated on delineating three primary elements within the articles: the abstract, study findings and discussions. The rationale behind this focused approach stemmed from the overarching objective of the Systematic Literature Review (SLR), which aimed to meticulously review the perspectives or definitions articulated by scholars concerning extremism and religious extremism, as delineated in prior research. Sections of the articles were thoroughly scrutinized to ascertain the presence of pertinent information. To facilitate subsequent analysis, the extracted data were methodically tabulated. Subsequently, the extracted data underwent meticulous analysis. Given that this SLR adopts an integrative approach, synthesizing diverse study designs encompassing various study designs (quantitative, qualitative and mixed methods), a qualitative synthesis was deemed most appropriate for analysis. Specifically, the analysis employed the conventional content analysis approach as outlined by Hsieh and Shannon (2005) to guide the data analysis process.

Conventional content analysis is particularly well-suited for studies where existing theory or literature on the phenomenon is limited or contested—conditions that apply to the definitional challenges surrounding extremism. Rather than applying predefined categories, this method allows themes and categories to emerge organically from the data itself. It involves a process of inductive category development, where researchers immerse themselves in the text to identify patterns, categories and sub-themes directly from the content. This approach enables a deeper and more nuanced understanding of the phenomenon under investigation by allowing findings to be grounded in the actual data rather than in existing theoretical frameworks. In line with Hsieh and Shannon’s (2005) methodology, the researchers examined each extracted finding and generated initial codes. These codes were then compared to identify similarities, recurring ideas or conceptual relevance. Through this iterative process, broader themes and sub-themes were established. This approach aligns with the method’s strength of capturing contextual meaning and latent insights embedded in textual data, as it goes beyond surface-level categorization to uncover the underlying dimensions of the concept.

These thematic categories reflect the complexity and multidimensional nature of the way extremism is framed and understood across the academic literature. The advantage of using the conventional content analysis method is that it allowed the study to derive categories directly from the data, free from researcher bias or theoretical imposition, thereby enhancing the authenticity and reliability of the findings.

Results

Following a comprehensive search and screening process, a total of 11 articles were identified as eligible for inclusion in this systematic literature review. These articles were published between 2018 and 2023, with two published in 2023, one in 2022, three in 2021, two in 2020, one in 2019 and one in 2018. Each of the articles was published in the following journals: International Journal of Developmental Sciences; Behavioural Sciences; Journal for Deradicalization; Criminal Justice Review; Revista Genero & Direito; Critical Studies on Terrorism; Intellectual Discourse; Ecclesiastical Law Journal; Cypriot Journal of Educational Sciences; Journal of Higher Education Theory and Practice; British Educational Research Journal.

The data extracted from these articles were analyzed and resulting in the identification of three overarching themes related to the conceptualization of extremism and religious extremism, namely belief, behaviour and no universal definition; four sub-themes were identified, namely uncompromised, biased interpretation, specific society and violation of true teaching (Refer Table 4).

Table 4 The Main Themes and Subthemes.
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The behaviour theme appeared most frequently across the included articles, discussed explicitly in 8 out of 11 studies. This was followed by the belief theme, addressed in 7 studies, while the issue of definitional ambiguity or no universal definition was evident in 5 articles, was treated as a cross-cutting issue present in all reviewed studies.

Moreover, the methodological approaches used in the selected articles varied. The majority of studies employed qualitative designs such as document analysis, discourse analysis or conceptual framing. A few incorporated quantitative approaches, while purely mixed-method was rare. This suggests a strong reliance on interpretive and context-based methodologies in the study of extremism and religious extremism.

Notably, several studies (e.g., Rahman 2018; Asal et al. 2020; Bidova et al. 2020; Abdellatif 2022 and Saada 2023) emphasized the role of rigid belief systems and ideological intolerance as precursors to extremism. Others (e.g., Akhmetova et al. 2021; Riedel 2021) highlighted the impact of policy and institutional bias on shaping public perceptions of extremism. Meanwhile, studies such as Akhmetova et al. (2021), Breidlid (2021) and al-Slaihat (2023) emphasized the influence of socio-political and economic contexts on extremist behaviour. In relation to the sub-theme violation of true teaching, this was addressed in studies by Pauwels and Hardyns (2018), Rahman (2018), Asal et al. (2020), Bidova et al. (2020), Breidlid (2021) and Saada (2023), all of which explored how distorted or excessive interpretations of ideological or religious principles may lead to extremism. Additionally, the issue of no universal definition was evident in studies by Pauwels and Hardyns (2018), Dawson (2019), Breidlid (2021), Akhmetova et al. (2021) and Riedel (2021), highlighting the persistent lack of conceptual clarity and the contextual variations in how extremism is framed and applied.

Collectively, these findings illustrate the complexity of defining extremism, as it intersects with religious interpretation, political discourse and social structure. These findings underscore the need for greater definitional clarity, as well as context-sensitive frameworks that can distinguish between radical thought, ideological dissent, and violent extremism. The diversity of themes identified and the methodological richness of the studies reviewed also indicate a gap in unified theoretical frameworks—an area warranting further empirical and conceptual exploration.

Discussions

Taxonomy of scholarly definitions: mapping the literature on extremism and religious extremism

This systematic literature review sought to explore the way of extremism and religious extremism are defined across disciplines and to synthesize these perspectives into a structured taxonomy. The analysis reveals that the existing body of literature lacks a uniform or universally accepted definition of these terms. Instead, extremism is frequently described through diverse lenses—legal, psychological, sociopolitical and religious—leading to fragmented interpretations across studies (Schmid 2014; Dawson 2019; Pauwels & Hardyns 2018).

Three dominant thematic clusters emerged from the literature: belief, behaviour and the no universal definition. Under the belief theme, scholars such as Rahman (2018), Asal et al. (2020), Bidova et al. (2020), Abdellatif (2022) and Saada (2023) emphasize the role of uncompromised ideological rigidity and overvalued ideas that become resistant to change over time. These beliefs are not inherently pathological but can foster exclusionary worldviews and intolerance of alternative perspectives. Borum (2011) and Hogg and Adelman (2013) underscore that such beliefs may evolve into violence-supportive ideologies, particularly when reinforced by social identity uncertainty or charismatic leadership.

Beliefs function akin to “internal commands” to the brain, guiding individuals in how they interpret events when they hold something to be true. When individuals lack beliefs or struggle to access them, they often experience a sense of disempowerment (Rao et al. 2009). In extreme cases, when such beliefs are translated into actions that inflict harm upon others, they can be deemed manifestations of violent extremism (Ismail et al. 2018; Borum 2011). These insights point to the psychological depth and internalization of belief systems in the development of extremist identities.

The sub-theme of biased interpretation captures how religious and ideological beliefs are manipulated, often for political or personal gain. Studies by Akhmetova et al. (2021) and Riedel (2021) illustrate how policies such as the UK’s Prevent Duty can institutionalize bias by disproportionately targeting certain groups, particularly Muslims. These studies demonstrate the way bias in the perception of ideas can be manipulated to advance political, intellectual, or policy-oriented agendas. Similarly, Wiktorowicz (2005) explains that religious extremism can be propagated through selective textual interpretation and social influence, often disconnected from core doctrinal teachings. The urgency to establish a clear definition of extremism arises from the persistent confusion surrounding its scope and subsets (Dono et al. 2024; Striegher 2015).

The theme of behaviour situates extremist action within the sociopolitical realities of specific societies. Breidlid (2021), Akhmetova et al. (2021) and al-Slaihat (2023) emphasize that acts labelled as extremist in one cultural or legal context may be seen as legitimate dissent in another. For example, extremism in Kenya and Jordan is shaped by governance issues, economic hardship and politicized religious narratives. Heath-Kelly (2013) added that Western security frameworks often ignore structural drivers of radicalization and reducing complex behaviour to simplistic ideological explanations.

The sub-theme violation of true teaching explores the traits of extremism that often emerge from distorted interpretations of ideological or religious principles. Saada (2023), Bidova et al. (2020) and Pauwels and Hardyns (2018) present evidence of religious extremism that deviates from core teachings of Islam as well as endorsing practices that are excessive or unorthodox. The studies also reveal that such violations are not limited to religious misinterpretation but can be found in systems of governance. For example, Breidlid (2021) extends the critique to broader governance failures and human rights violations, noting that some systems mislabel legitimate dissent as extremism. These elements are crucial in elucidating the meaning or definition of extremism itself, which is contained within the sub-theme of the violation of true teaching (Ismail et al. 2018). Similar insights can be drawn from Wiktorowicz (2005), who highlights the role of selective textual interpretation and charismatic authority in constructing religiously justified extremist identities.

A central thread running across all themes is the no universal definition, which is the absence of a universally accepted definition of extremism. Scholars such as Akhmetova et al. (2021), Breidlid (2021), Riedel (2021), Dawson (2019) and Pauwels and Hardyns (2018) emphasize that definitional inconsistencies hinder both policy-making and scholarly coherence. Pauwels and Hardyns (2018) corroborate this notion, emphasizing the proliferation of diverse definitions of extremism. Such definitional variations often stem from the legal frameworks adopted within specific national contexts (Sotlar 2004). National legal and policy environments embed culturally specific assumptions, as seen in the UK’s narrow focus on Islamist threats or Kenya’s conflation of political dissent with extremism. The critique is not merely academic; it has real-world consequences in counter-terrorism efforts, human rights protection and interfaith dialogue. Bartlett and Miller (2012) have likewise argued that without definitional clarity, efforts to counter extremism risk being overly broad, ideologically biased and counterproductive.

Towards a standardized conceptual framework for extremism and religious extremism

Given the definitional fragmentation observed across the reviewed literature, this study attempts to move toward a standardized conceptual framework by identifying recurring components and patterns. Extremism, based on this review, may be defined as:

“The adoption or promotion of rigid ideological beliefs that reject diversity and tolerate little or no dissent, often resulting in or justifying behaviour that contravenes widely accepted social, moral or legal norms”.

Religious extremism, as a subset, narrows its scope to ideological rigidity that draws legitimacy from distorted interpretations of sacred texts or doctrines. This distinction is crucial because, while extremism may encompass political, nationalist or secular ideologies, religious extremism adds a sacralized dimension that often involves divine justification and communal identity enforcement (Saada 2023; Bidova et al. 2020).

Importantly, this review supports the view that not all radical beliefs or dissenting views qualify as extremism. Rather, the defining threshold lies in the translation of beliefs into coercive or harmful action and in the refusal to engage in dialogue or accommodate difference. A comprehensive framework must therefore include ideological commitment, interpretive rigidity, behavioural expression and context as core definitional elements.

Moving forward, future research and policymaking should avoid overly broad definitions that risk infringing on civil liberties. Instead, the emphasis should be on contextual specificity, normative neutrality and distinguishing between dissent and danger. Interdisciplinary collaboration between religious scholars, psychologists, legal theorists and political scientists is essential to refine and apply this framework effectively across global contexts.

Limitations and future directions

Several limitations were acknowledged in this study. Firstly, the small number of articles included in the final analysis. Although 510 articles were initially identified but only 11 met the inclusion criteria after screening. While this shows some range in disciplinary perspectives, the number is still small and may not capture the full scope of research on this topic. Second, the literature was collected only from two major databases: Web of Science (WoS) and Scopus. Although these are reputable sources, limiting the search to only these databases may have excluded relevant studies from other platforms or regional sources. Future reviews could benefit from including additional databases or grey literature to broaden the scope. Third, the thematic analysis used in this review relies on qualitative interpretation. Although the study followed systematic frameworks such as PRISMA, SPIDER and the content analysis method by Hsieh and Shannon (2005), the process of coding and theme development still involves a degree of subjectivity. Efforts were made to ensure consistency, but interpretive bias cannot be fully avoided. Another limitation is the wide range of disciplines covered by the selected studies. These studies came from different fields such as criminology, education, psychology, law and religious studies. This diversity adds depth but also creates challenges in maintaining consistent definitions and interpretations. The variation in how different disciplines define extremism may contribute to the lack of a clear and unified understanding. Lastly, the study only included articles written in English. This limits the findings to English-language perspectives and may exclude important viewpoints from non-English-speaking countries. Since extremism is shaped by cultural and social contexts, including studies from other languages, would provide a more complete picture.

Despite these limitations, this study offers several directions for future research. Future studies could include articles in other languages and use a wider range of databases to ensure broader representation. Comparative studies across countries could help explore the way national laws and policies define and respond to extremism. Research could also focus on different cultural contexts of communities in understanding extremism, beyond official or Western definitions. There is also a need to develop a more unified framework that brings together perspectives from different fields such as law, psychology, religion and politics. Finally, future research should also consider how certain definitions of extremism may reflect ideological or political bias, especially when used in policy or media.

Conclusion

In conclusion, this systematic literature review (SLR) has explored various dimensions of extremism and religious extremism through an examination of scholarly perspectives and empirical studies. Extremism in a broad concept encompasses a spectrum of ideologies and behaviours characterized by rigid beliefs and an intolerance for dissent and often leading to actions that violate societal norms and ethical principles. Apart from this, religious extremism represents a specific subset and exploited to justify intolerance and violent actions. The analysis has revealed several key themes, including beliefs and behaviour, which are integral to understanding the manifestations and implications of extremism. Beliefs serve as fundamental guiding principles that shape individuals’ perceptions of the world and their actions. Extremist beliefs, characterized by unwavering commitment and intolerance towards dissenting views, can lead to behaviours that violate societal norms and ethical principles. Intellectual extremism, a distinct form of extremism prevalent among university students, further illustrates the detrimental effects of rigid belief systems on intellectual growth and social cohesion. Moreover, the lack of consensus in defining extremism has been highlighted, with scholars and legislative frameworks offering diverse interpretations and definitions. This ambiguity poses challenges in identifying and addressing extremism effectively, particularly within specific societal contexts.

Legislative efforts such as the Prevent Duty in the UK aim to mitigate the risks of radicalization and terrorist activities by identifying and supporting individuals susceptible to extremist ideologies. However, such initiatives have faced criticism for their broad definitions and potential infringements on human rights. Moving forward, it is imperative to foster dialogue and collaboration among scholars, policymakers and communities to develop nuanced definitions of extremism and religious extremism that account for diverse perspectives and contexts. Additionally, efforts to prevent and counteract extremism should prioritize education, social reforms and the promotion of democratic values and mutual respect. By addressing the root causes of extremism and fostering inclusive societies, we can work towards mitigating the risks posed by extremist ideologies and promoting peace and stability globally.