WordNet (r) 3.0 (2006):

fade out
    v 1: become weaker; "The sound faded out" [syn: dissolve,
         fade out, fade away]

Moby Thesaurus II by Grady Ward, 1.0:

142 Moby Thesaurus words for "fade out":
   FCC, FM broadcasting, Federal Communications Commission, abatement,
   abridgment, alleviation, atmospherics, attenuation, be annihilated,
   be consumed, be destroyed, be gone, be no more, be wiped out,
   blackout, blanch, blaring, blasting, bleach, bleach out,
   blind spot, blocking, broadcasting, cease, cease to be,
   cease to exist, change color, contraction, crawling, creeping,
   dampening, damping, decrease, decrement, decrescence, deduction,
   deflation, dematerialization, dematerialize, depart, departure,
   depreciation, depression, die, die away, die out, diminishment,
   diminution, disappear, disappearance, disappearing, dispel,
   disperse, dispersion, dissipate, dissipation, dissolution,
   dissolve, dissolving, do a fade-out, drift, dwindle, dying,
   dying off, eclipse, elimination, erasure, erode, evanesce,
   evanescence, evaporate, evaporation, exit, expire, extenuation,
   extinction, fade, fade away, fadeaway, fadeout, fading, flee, fly,
   go, go away, going, grow pale, hide, interference, languishment,
   leave no trace, leave the scene, lessening, letup, lose color,
   lowering, melt, melt away, melting, miniaturization, mitigation,
   mixing, noise, occultation, pale, pass, pass away, pass out,
   passing, perish, peter out, radiobroadcasting, reception,
   reduction, relaxation, retire from sight, sagging, scaling down,
   simplicity, sink, sink away, standard broadcasting, static,
   subtraction, suffer an eclipse, tone control, transmission,
   turn pale, turn white, vanish, vanish from sight, vanishing,
   vanishing point, vestigial transmission, volume control, wan,
   waste, waste away, weakening, wear away, whiten, wipe