The paper addresses the variability of Czech phrasemes, i.e. semantically non-compositional multiword units, in current use represented by corpora, the variability being the result of linguistic creativity on the part of text authors. It also asks what, in fact, identifies a phraseme. A basic, original phraseme has a certain meaning that cannot be inferred from the meaning of its components, and if it is modified, made more topical and up-to-date, either the original meaning is entirely or partially preserved, or the modified phraseme acquires a totally new meaning. Some phrasemes allow for multiple modifications, while others are more rigid. The article examines different types of lexical/syntactic/morphological/semantic alteration ...