decline

> decline
(verb)
incline, lean, slope.
decay, droop, fail, flag, languish, pine, sink.
degenerate, depreciate, deteriorate.
decrease, diminish, dwindle, fade, ebb, lapse, lessen, wane.
avoid, refuse, reject.
inflect, vary.

> decline
(noun)
decadence, decay, declension, declination, degeneracy, deterioration, diminution, wane.
atrophy, consumption, marasmus, phthisis.
declivity, hill, incline, slope.