Declineable

Declineable is an adjective used primarily in linguistics to describe a word that can be declined or inflected for grammatical categories such as case, number, and gender. In languages with rich morphology, many nouns, adjectives, and pronouns are declineable, yielding distinct forms for different syntactic contexts. By contrast, indeclinable words do not change form; in English, for example, most prepositions and many adverbs are indeclinable, and modern English nouns typically show little or no true case inflection.

In describing a language’s inventory, linguists distinguish between declineable and indeclinable items. Declineable words participate in declensions or agreement patterns, whereas indeclinable words remain invariant across grammatical roles. This concept helps explain how sentences convey function and meaning through morphology rather than word order alone. English, Latin, Greek, and many other languages illustrate the spectrum: Latin nouns and adjectives are fundamentally declineable, while English has largely moved toward indeclinable noun forms and relies more on word order and prepositions.

Etymologically, declineable derives from decline + -able, with related terms such as declinable and inflectable. The spelling declineable is less common than declineable or declinable, and usage varies by author and tradition. In contemporary linguistics, declension and inflection are more widely used terms; declineable remains a descriptive label for words that still exhibit morphological variation in certain languages.

See also: inflection, declension, indeclinable, inflectable.