Idioms are a special case of multi-word expressions in that their meaning cannot be compositionally constructed from the meaning of the single constituents. The question of how the idiomatic meaning is assembled remains an unsettled issue in psycholinguistic research. The present study examines whether the figurative meaning of an idiom is recognized if critical idiomatic constituents, such as the noun, verb, or preposition, are modified. In three paraphrase experiments, participants saw (a) the canonical idiomatic phrase (e.g., She reached for the stars), (b) the idiomatic phrase with a modified constituent (e.g., She reached/grasped for/at the stars/planets), or (c) a matched literal control sentence (e.g., She reached for the sweets) and rated on a scale from 1 (not at all) - 7 (completely) how strongly the sentence reflected the meaning of a paraphrase of the idiom (e.g., She has always aspired to unattainable goals). Sentence type and constituent type strongly affected paraphrase ratings with highest ratings for canonical idiomatic phrases, lowest ratings for control sentences, and ratings in between for idioms with modified constituents. Further, idioms with modified verbs were rated higher in matching the figurative meaning than idioms with modified prepositions or nouns. Overall these findings indicate that the figurative meaning was assembled in spite of the modifications. We conclude that idioms are not fully ‘semantically fixed’ but allow for some flexibility in the processing of idioms. Modified constituents that activate meanings similar to those of the canonical constituents will co-activate the figurative meaning of the idiom together with the other idiomatic constituents. We discuss psycholinguistic models on idiom comprehension.