non-compositional

alternative noncompositional

1. Not compositional.

   An idiom is defined as a non-compositional multiword expression, one whose meaning cannot be deduced from the definitions of the component words.

   2019, Alyssa Hwang, Christopher Hidey, Confirming the Non-compositionality of Idioms for Sentiment Analysis

   2 more examples

   Any natural language processing system that does not have a knowledge of non-compositional idioms and their interpretation will make mistakes. Previous authors have attempted to automatically identify these expressions through the property of non-substitutability: similar words cannot be successfully substituted for words in non-compositional idiom expressions without changing their meaning.

   2007, Faye Rochelle Baron, Identifying non-compositional idioms in text using WordNet synsets

   The recognition and accurate translation of proper nouns, many of which are bilingually non-compositional, are a major issue in MT and other NLP applications. This is especially true for Chinese and Japanese, whose scripts present linguistic and algorithmic challenges not found in other languages.

   2019, Jack Halpern, Lexicographic Criteria for Selecting Multiword Units for MT Lexicons

   Antonyms: compositional