de·clen·sion / diˈklenshən/ • n. 1. (in the grammar of Latin, Greek, and other languages) the variation of the form of a noun, pronoun, or adjective, by which its grammatical case, number, and gender are identified. ∎  the class to which a noun or adjective is assigned according to this variation.2. poetic/lit. a condition of decline or moral deterioration.DERIVATIVES: de·clen·sion·al / -shənl/ adj.

declension XV. repr. (O)F. déclinaison, f. décliner DECLINE, after L. dēclīnātiō DECLINATION.