Résumé : Dans cette étude, nous projetons d’observer le devenir des défigements formés par ajout d’affixe, de formuler des hypothèses sur les conditions qui conduisent à un nouveau figement, celui de l’expression défigée qui va donc coexister avec le premier figement. C’est le cas de ‘commerce inéquitable’, défigement formé par ajout du préfixe « in- » à la séquence figée ‘commerce équitable’ qui a sans doute acquis à son tour le statut de lexie.
Abstract : It is commonly admitted that fixed multi words expressions (MWEs), term preferred in NLP, or fixed expressions and idioms (FEIs), constitute more or less the half-part of the lexicon of any language, and the way one handles them is thus essential to speak like native speakers. But since linguistics is based on the decomposition of minimal language units, we find noteworthy that they rarely take part of dictionaries. In this study, although we agree that stability and fixedness differ among FEIs and that each of them shows a characteristic behaviour on the morphological, syntactical, and semantic levels, we will only focus on the hermeneutical conditions of their variation, and more particularly on puns. In a few cases, puns are obtained by derivation of one or more segments of the FEI and the lexicalisation of modified FEIs is thus particularly interesting: let us take the case of “commerce equitable” (788 000 occurrences following Google.fr and 20 200 for the modified FEI, “commerce inéquitable”). In this example, the modified FEI seems to meet the needs of communication: “commerce inequitable” can be used in every discourse situation dedicated to neglect the improvement of workers conditions around the world. This article deals with the conditions that explain the lexicalisation of new FEIs derived on the basis of older ones.