The Collaborative International Dictionary of English v.0.48:

Destroy \De*stroy"\, v. t. [imp. & p. p. Destroyed; p. pr. &
   vb. n. Destroying.] [OE. destroien, destruien, destrien,
   OF. destruire, F. d['e]truire, fr. L. destruere, destructum;
   de + struere to pile up, build. See Structure.]
   1. To unbuild; to pull or tear down; to separate virulently
      into its constituent parts; to break up the structure and
      organic existence of; to demolish.
      [1913 Webster]

            But ye shall destroy their altars, break their
            images, and cut down their groves.    --Ex. xxxiv.
                                                  13.
      [1913 Webster]

   2. To ruin; to bring to naught; to put an end to; to
      annihilate; to consume.
      [1913 Webster]

            I will utterly pluck up and destroy that nation.
                                                  --Jer. xii.
                                                  17.
      [1913 Webster]

   3. To put an end to the existence, prosperity, or beauty of;
      to kill.
      [1913 Webster]

            If him by force he can destroy, or, worse,
            By some false guile pervert.          --Milton.

   Syn: To demolish; lay waste; consume; raze; dismantle; ruin;
        throw down; overthrow; subvert; desolate; devastate;
        deface; extirpate; extinguish; kill; slay. See
        Demolish.
        [1913 Webster]

WordNet (r) 3.0 (2006):

destroy
    v 1: do away with, cause the destruction or undoing of; "The
         fire destroyed the house" [syn: destroy, destruct]
    2: destroy completely; damage irreparably; "You have ruined my
       car by pouring sugar in the tank!"; "The tears ruined her
       make-up" [syn: destroy, ruin]
    3: defeat soundly; "The home team demolished the visitors" [syn:
       demolish, destroy]
    4: put (an animal) to death; "The customs agents destroyed the
       dog that was found to be rabid"; "the sick cat had to be put
       down" [syn: destroy, put down]

Moby Thesaurus II by Grady Ward, 1.0:

278 Moby Thesaurus words for "destroy":
   abolish, abuse, afflict, aggrieve, annihilate, annul, assault,
   atomize, attack, baffle, balk, barbarize, batter, beat,
   beat all hollow, beat hollow, befoul, bereave of life, best,
   bewitch, blast, blight, botch, brave, break down, break up,
   bring to ruin, brutalize, burn, butcher, cancel out, carry away,
   carry off, carry on, challenge, checkmate, chloroform, circumvent,
   condemn, confound, confront, confute, consume, contradict,
   contravene, corrupt, counter, counteract, countermand, counterwork,
   cripple, cross, crucify, crush, curse, cut down, cut off, damage,
   damn, dash, deal destruction, decapitate, decimate, defeat, defile,
   defy, demolish, deny, deprave, depredate, deprive of life,
   desolate, despoil, devastate, devitalize, devour, disable,
   disadvantage, discomfit, disconcert, discountenance, dish,
   dismantle, dispatch, dispose of, disprove, disrupt, disserve,
   dissolve, distress, do a mischief, do away with, do evil, do for,
   do ill, do in, do to death, do wrong, do wrong by, doom, drub,
   dynamite, elude, end, enfeeble, engorge, envenom, eradicate,
   execute, exhaust, exterminate, extinguish, extirpate, finish,
   finish off, fix, flummox, foil, frustrate, get into trouble, go on,
   gobble, gobble up, gut, gut with fire, hammer, harass, harm, havoc,
   hex, hide, hors de combat, hurt, immolate, impair, incinerate,
   infect, injure, interfere with, jinx, kill, knock the chocks,
   lambaste, lather, launch into eternity, lay in ruins, lay waste,
   lick, liquidate, loot, lynch, make away with, maltreat, mangle,
   mar, martyr, martyrize, maul, menace, mistreat, molest, mug,
   mutilate, negate, neutralize, nonplus, nullify, outclass, outdo,
   outfight, outgeneral, outmaneuver, outpoint, outrage, outrun,
   outsail, outshine, overthrow, overturn, perplex, persecute,
   pillage, play havoc with, play hob with, poison, pollute,
   prejudice, pull down, pulverize, purge, put, put away, put down,
   put to death, put to sleep, quench, rage, ramp, rampage, rant,
   rape, ravage, rave, raze, refute, remove from life, reverse, riot,
   roar, rub out, rubble, ruin, ruinate, sabotage, sack, sacrifice,
   savage, scathe, scotch, settle, shatter, shipwreck, shoot, skin,
   skin alive, slaughter, slay, smash, sow chaos, spike, spoil,
   starve, stonewall, stop, storm, stump, swallow up, taint,
   take life, take off, tear, tear around, tear down, terminate,
   terrorize, thrash, threaten, throw into disorder, thwart, torment,
   torture, trash, trim, triumph over, trounce, unbuild, undermine,
   undo, unleash destruction, unleash the hurricane, unmake, upheave,
   upset, vandalize, vaporize, violate, waste, weaken, whip, wipe,
   wipe out, worst, wound, wrack, wreak havoc, wreak havoc on, wreck,
   wrong