This article disputes the premise dominant in moral philosophy and the social sciences that a strict definition of terrorism is needed in order to evaluate and confront contemporary political violence. It argues that a definition of terrorism is not only unhelpful, but also impossible if the historicity and flexibility of the concept are to be taken seriously. Failure to account for terrorism as a historical phenomenon produces serious analytical and epistemological problems that result in an anachronistic, ahistorical, and reductive understanding. (...) Because there are no historically or contextually stable answers to the question what terrorism is, this article argues for a novel account of terrorism that replaces the attempt to define terrorism with an analysis of its meaning and function within a specific context. (shrink)