THESAURUS
be gone
be all over, be consumed, be past, cease, cease to be, cease to exist, dematerialize, depart, die, die away, die out, disappear, dispel, disperse, dissipate, dissolve, do a fade-out, dwindle, elapse, erode, evanesce, evaporate, exit, fade, fade away, fade out, flee, fly, go, go away, have run out, hide, lapse, leave no trace, leave the scene, melt, melt away, pass, pass away, pass out, perish, retire from sight, sink, sink away, suffer an eclipse, vanish, vanish from sight, waste, waste away, wear away
ROGET THESAURUS
be gone
Departure
VB
depart, go away, take one's departure, set out, set off, march off, put off, start off, be off, move off, get off, whip off, pack off, go off, take oneself off, start, issue, march out, debouch, go forth, sally forth, sally, set forward,
be gone, hail from, leave a place, quit, vacate, evacuate, abandon, go off the stage, make one's exit, retire, withdraw, remove, vamoose, vamose, go one's way, go along, go from home, take flight, take wing, spring, fly, flit, wing one's flight, fly away, whip away, embark, go on board, go aboard, set sail' put to sea, go to sea, sail, take ship, hoist blue Peter, get under way, weigh anchor, strike tents, decamp, walk one's chalks, cut one's stick, take leave, say good bye, bid goodbye, disappear, abscond, entrain, inspan.
Disappearance
VB
disappear, vanish, dissolve, fade, melt away, pass, go, avaunt, evaporate, vaporize,
be gone, leave no trace, leave 'not a rack behind', go off the stage, suffer an eclipse, undergo an eclipse, retire from sight, be lost to view, pass out of sight, lose sight of, efface.