Incels (a shortened term for "involuntary celibates") are heterosexual men who blame women and society for their lack of romantic success. They are part of the online "manosphere" of misogynists and men with a strong sense of grievance against women. Incels are the most violent community within the manosphere, having perpetrated a number of deadly attacks against women. The term "incel" was originally coined in 1993 by a young Canadian woman as a label for her own single status before it was used to define a community that is a majority males and posthumously assigns the tern to violent actors.

This database provides an overview of many of the terms and individuals used by or associated with movements and groups that subscribe to and/or promote extremist or hateful ideologies.