declension

Concise Oxford English Dictionary © 2008 Oxford University Press:
declension /dɪˈklɛnʃ(ə)n/

▶noun

• 1 Grammar 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 archaic a condition of decline or moral deterioration.

– derivatives
declensional adjective.

– origin ME declinson, from OFr. declinaison, from decliner ‘to decline’.