1.change toward something smaller or lower
2.a condition inferior to an earlier condition; a gradual falling off from a better state
3.a gradual decrease; as of stored charge or current
4.a downward slope or bend
1.grow worse;
Conditions in the slum worsened
2.refuse to accept;
He refused my offer of hospitality
3.show unwillingness towards;
he declined to join the group on a hike
4.grow smaller;
Interest in the project waned
5.go down;
The roof declines here
6.go down in value;
the stock market corrected
7.inflect for number, gender, case, etc., "in many languages, speakers decline nouns, pronouns, and adjectives"