1. a polite refusal of an invitation

Synonym: regrets

2. (astronomy) the angular distance of a celestial body north or to the south of the celestial equator
expressed in degrees
used with right ascension to specify positions on the celestial sphere

Synonym: celestial latitudedec

3. a downward slope or bend

Synonym: descentdeclivityfalldeclinedeclensiondownslope

4. a condition inferior to an earlier condition
a gradual falling off from a better state

Synonym: decline