1. (Intrans.) Baisser.
2. (Intrans.) Faiblir. Sa santé décline.
3. Refuser. Il décline votre offre.
1. To go down.
2. To grow smaller; SYN. go down, wane.
3. Said of nouns, pronouns, and adjectives: to add case endings (accusative, dative, etc.), in certain languages.