nondeclined

Nondeclined is a linguistic term used to describe a word or word class that does not participate in the declension system of a language. In languages that mark grammatical categories such as case, number, or gender on nouns, pronouns, adjectives, or other parts of speech, a nondeclined form remains unchanged across different grammatical contexts. The more common term for this concept is indeclinable; nondeclined is a variant label found in some grammars or descriptive works.

In practice, nondeclined items are typical in analytic or isolating languages, where little or no inflection expresses grammatical relations. For example, in languages like Mandarin Chinese or Vietnamese, nouns and other parts of speech generally do not change form to indicate case or number. Quantity or grammatical relations are often conveyed through separate words, particles, or word order rather than through inflection on the target word itself.

Nondeclined forms also appear in morphologically rich languages. In Turkish, for instance, adjectives tend to be nondeclined: they do not take case endings themselves, while the nouns they modify may receive case endings. This contrasts with the declension of nouns or pronouns, which may reflect case or number.

The concept helps grammars describe how a word behaves within a language’s morphology. It is distinct from terms like declinable or inflected, which describe forms that do change. In summary, nondeclined (or indeclinable) words remain invariant across the grammatical categories that would otherwise cause form changes in a language. See also indeclinable, declension, morphology.