What is right-wing extremism? At first glance, the question would seem easy to answer. But it involves various dimensions that are not immediately obvious, because it actually covers two complexes that need to be systematically differentiated before an answer can be formulated. On the one hand, it obviously involves identifying the factors and aspects informing a particular worldview and/or conduct that would justify calling someone or something right-wing extremist. This would cover the basic elements of the far-right worldview and its resulting political practices—in other words, investigating the relationship between theory and application in right-wing extremism, analyzing what characteristics distinguish the far-right worldview conceptually and examining how these ideas and attitudes lead to specific social and/or political actions. On the other hand—and this is less obvious—the investigation must also consider how the term “right-wing extremism” has come to be applied when categorizing particular political phenomena, be it as an additional label or an essentialist one; in other words, whether, when and why one chooses to speak of right-wing extremism, or alternatively right-wing populism, neo-fascism, neo-Nazism or the radical right. While the term “right-wing extremism” has now become established as an overall label within German scholarship, politics and media, this has certainly not always been the case (e.g., in West Germany until the early 1970s, public debate was dominated by the terms neo-Nazism and neo-fascism, while the 1990s also saw intensive debate on whether the preferred term should be “right-wing extremism” or “right-wing radicalism”; cf. Salzborn 2015c). Even now, there are still multiple terms competing for the status of overarching label, so the question of “What is right-wing extremism?” must also involve an examination of not only the descriptive label but also of what exactly is being described (on the question of terminology, cf. Hempel and Oppenheim 1948).