To cease living
decease, expire, pass away, pass on, depart, perish, succumb, go, commit suicide, suffocate, lose one's life, cease respiration, emit the last breath, relinquish life, suffer death, cease to exist, come to a violent end, come to naught, drown, hang, fall, meet one's death, be no more, end one's earthly career, be taken, drop dead*, go to glory, go up*, go off*, return to the earth, fall asleep*, be done for*, catch one's death*, fade away, rest in peace, go belly up*, be numbered with the dead, join the choir invisible, pay the supreme sacrifice, go to one's last home, cross the Styx, pass over to the great beyond, give up the ghost, go the way of all flesh, pay the debt of nature, shuffle off this mortal coil, slide into oblivion, become one with nature, awake to immortal life, join the great majority, turn to dust, return to dust, close one's eyes, cash in one's chips*, cash in*, go west*, push up daisies*, buy the farm*, kick the bucket*, shut up shop*, answer the last call*, bite the dust*, lay down one's life*, breathe one's last, croak*, bite the bullet*, kick in*, go to one's reward, be gathered to one's fathers, keel over*, conk out*, go home feet first*, check out*, burn out*, kick off*, end one's days, go by the board*.
To cease existing
stop, extinguish, dissolve, disappear, die out, go out, recede, vanish, evanesce, burn out, be heard of no more, come to nothing, evaporate, become extinct, die off, be null and void, be no more, leave not a trace behind, discontinue, go blooey*, go pfft*; see also disappear, stop 2.
To decline as though death were inevitable
fade, wither, decline, wane, sink, wear away, ebb, droop, lapse, retrograde, lose active qualities, run low, rot, crumble, diminish, deteriorate, molder, rankle, dilapidate, die out, die down, melt away, subside, go bad*, totter to a fall*, go downhill*; see also decay, weaken 1.
die is the basic, simple, direct word meaning to stop living or to become dead; decease, expire, and ?pass away are all euphemisms, decease being also the legal term, expire meaning literally to breathe one's last breath, and ?pass away suggesting a transition to another state; perish implies death by a violent means or under difficult circumstances
To cease living:decease, demise, depart, drop, expire, go, pass away, pass (on), perish, succumb. (Informal) pop off. (Slang) check out, croak, kick in, kick off. Idioms: bite the dust, breathe one's last, cash in, give up the ghost, go to one's grave, kick the bucket, meet one's end (or Maker), pass on to the Great Beyond, turn up one's toes. See live
To cease to exist.Away or out: disappear, expire. See live
To become or cause to become less active or intense.Away, down, off, or out: abate, bate, ease (off or up), ebb, fall, fall off, lapse, let up, moderate, remit, slacken, slack off, subside, wane. See increase
To become inaudible.Away, out, or down: fade, fade out. See increase