Any definition presupposes a theoretical grid giving sense to what is defined. This sense – as the very notion of definition asserts – can only be established on the basis of differentiating the defined term from something else that the definition excludes. This, in turn, presupposes a terrain within which those differences as such are thinkable. It is this terrain which is not immediately obvious when we call a movement (?), an ideology (?), a political practice (?) populist. In the first two cases – movements or ideologies – to call them populist would involve differentiating that attribute from other characterisations at the same defining level, such as ‘fascist’, ‘liberal’, ‘communist’, etc. This engages us immediately in a complicated and ultimately self-defeating task: finding that ultimate redoubt where we would find ‘pure’ populism, irreducible to those other alternative characterisations. If we attempt to do so we enter into a game in which any attribution of a social or ideological content to populism is immediately confronted with an avalanche of exceptions. Thus we are forced to conclude that when we use the term some actual meaning is presupposed by our linguistic practices, but that such a meaning is not, however, translatable in any definable sense. Furthermore, we can even less, through that meaning, point to any identifiable referent (which would exhaust that meaning).