Merriam-Webster's Collegiate® Dictionary, 11th Edition
DECLINE
I. verb (declined; declining) see: lean
Date: 14th century
intransitive verb to turn from a straight course ; stray ,
2. to slope downward ; descend , to bend down ; droop , to stoop to what is unworthy,
3. to sink toward setting, to draw toward a close ; wane , to tend toward an inferior state or weaker condition , to withhold consent, to become less in amount , transitive verb to give in prescribed order the grammatical forms of (a noun , pro noun , or adjective ),
2. obsolete avert , avoid , to cause to bend or bow downward,
4. to refuse to undertake, undergo, engage in, or comply with , to refuse especially courteously , declinable adjective decliner noun Synonyms: see: decline
II. noun
Date: 14th century
the process of declining:, a gradual physical or mental sinking and wasting away, a change to a lower state or level , the period during which something is deteriorating or approaching its end , a downward slope, a wasting disease, see: deterioration