say it: di-KLAHYN
decline is a verb and noun meaning "grow worse". It carries 11 recorded senses.
inflect for number, gender, case, etc.
“in many languages, speakers decline nouns, pronouns, and adjectives”
change toward something smaller or lower
a condition inferior to an earlier condition; a gradual falling off from a better state
a gradual decrease; as of stored charge or current
a downward slope or bend
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for decline come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.