declension

(noun) the inflection of nouns and pronouns and adjectives in Indo-European languages.

(noun) process of changing to an inferior state. Synonyms: deterioration, decline in quality, worsening.

(noun) a downward slope or bend. Synonyms: descent, declivity, fall, decline, declination, downslope.

(noun) a class of nouns or pronouns or adjectives in Indo-European languages having the same (or very similar) inflectional forms. Examples: "The first declension in latin."