Noncompositionality

Noncompositionality in linguistics refers to the property of certain linguistic expressions whose meanings cannot be predicted from the meanings of their parts and the way they are syntactically combined. The principle of compositionality, attributed to Frege, holds that the meaning of a complex expression is determined by its structure and the meanings of its constituents; noncompositionality challenges this idea in restricted domains such as idioms and set phrases.

Common examples are idioms such as kick the bucket or spill the beans, whose meanings cannot be predicted from the literal meanings of the words. Multiword expressions may be fixed or conventionalized, as hit the road or take into account, and some phrasal verbs show nonliteral meanings that resist simple composition. Metaphor and metonymy also contribute to noncompositional interpretation, as in a wave of the future or the heart of the matter.

Scholars distinguish strong forms of noncompositionality, where the whole meaning is not derivable at all from parts, from weaker forms where context, world knowledge, or conventional usage yields partial nonliteral interpretation. Researchers in semantics and pragmatics study lexicalization, processing, and retrieval of MWEs, and how context affects their interpretation.

In computational linguistics, noncompositional expressions pose challenges for parsing, translation, and sentiment analysis. Approaches include treating MWEs as lexical units, compiling idiom dictionaries, and building models that capture figurative meaning and context. Understanding noncompositionality helps explain why language relies on fixed phrases, metaphor, and context-dependent interpretation.