decline

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To express polite refusal.
• intransitive verb To slope downward; descend.
• intransitive verb To bend downward; droop.
• intransitive verb To degrade or lower oneself; stoop.
• intransitive verb To deteriorate gradually; fail.
• intransitive verb To sink, as the setting sun.
• intransitive verb To draw to a gradual close.
• intransitive verb To refuse politely: synonym: refuse.
• intransitive verb To cause to slope or bend downward.
• intransitive verb Grammar To inflect (a noun, a pronoun, or an adjective) for number and case.
• noun The process or result of declining, especially.
• noun A gradual deterioration, as in numbers, activity, or quality.
• noun A downward movement or fall, as in price.
• noun A deterioration of health.
• noun A downward slope; a declivity.

from The Century Dictionary.

• In chess, to refuse to take a piece or pawn offered.
• noun A bending or sloping downward; a slope; declivity; incline.
• noun A descending; progress downward or toward a close.
• noun A failing or deterioration; a sinking into an impaired or inferior condition; falling off; loss of strength, character, or value; decay.
• noun In medicine: That stage of a disease when the characteristic symptoms begin to abate in violence.
• noun A popular term for any chronic disease in which the strength and plumpness of the body gradually diminish, until the patient dies: as, he is in a decline.
• noun The time of life when the physical and mental powers are failing. Quain.
• To cause to bend or slope; bend down; incline; cause to assume an inclined position; depress.
• To lower; degrade; debase.
• To decrease; diminish; reduce.
• To cause to deviate from a straight or right course; turn aside; deflect.
• To turn aside from; deviate from.
• To avoid by moving out of the way; shun; avoid in general.
• To refuse; refuse or withhold consent to do, accept, or enter upon: as, to decline a contest; to decline an offer.
• In grammar, to inflect, as a noun or an adjective; give the case-forms of a noun or an adjective in their order: as, dominus, domini, domino, dominum, domine.
• To bend or slant down; assume an inclined position; hang down; slope or trend downward; descend: as, the sun declines toward the west.
• To deviate from a right line; specifically, to deviate from a line passing through the north and south points.
• To deviate from a course or an object; turn aside; fall away; wander.
• To sink to a lower level; sink down; hence, figuratively, to fall into an inferior or impaired condition; lose strength, vigor, character, or value; fall off; deteriorate.
• To stoop, as to an unworthy object; lower one's self; condescend.
• To refuse; express refusal: as, he was invited, but declined.
• To approach or draw toward the close.
• To incline; tend.
• To incline morally; be favorably disposed.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To bend, or lean downward; to take a downward direction; to bend over or hang down, as from weakness, weariness, despondency, etc.; to condescend.
• intransitive verb To tend or draw towards a close, decay, or extinction; to tend to a less perfect state; to become diminished or impaired; to fail; to sink; to diminish; to lessen
• intransitive verb To turn or bend aside; to deviate; to stray; to withdraw
• intransitive verb To turn away; to shun; to refuse; -- the opposite of accept or consent.
• transitive verb To bend downward; to bring down; to depress; to cause to bend, or fall.
• transitive verb obsolete To cause to decrease or diminish.
• transitive verb To put or turn aside; to turn off or away from; to refuse to undertake or comply with; reject; to shun; to avoid
• transitive verb (Gram.) To inflect, or rehearse in order the changes of grammatical form of.
• transitive verb rare To run through from first to last; to repeat like a schoolboy declining a noun.