Verb
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""prices slumped"7. inflect for number, gender, case, etc., "in many languages, speakers decline nouns, pronouns, and adjectives"