The Collaborative International Dictionary of English v.0.48:

Spoil \Spoil\ (spoil), v. t. [imp. & p. p. Spoiled (spoild) or
   Spoilt (spoilt); p. pr. & vb. n. Spoiling.] [F. spolier,
   OF. espoillier, fr. L. spoliare, fr. spolium spoil. Cf.
   Despoil, Spoliation.]
   1. To plunder; to strip by violence; to pillage; to rob; --
      with of before the name of the thing taken; as, to spoil
      one of his goods or possessions. "Ye shall spoil the
      Egyptians." --Ex. iii. 22.
      [1913 Webster]

            My sons their old, unhappy sire despise,
            Spoiled of his kingdom, and deprived of eyes.
                                                  --Pope.
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   2. To seize by violence; to take by force; to plunder.
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            No man can enter into a strong man's house, and
            spoil his goods, except he will first bind the
            strong man.                           --Mark iii.
                                                  27.
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   3. To cause to decay and perish; to corrupt; to vitiate; to
      mar.
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            Spiritual pride spoils many graces.   --Jer. Taylor.
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   4. To render useless by injury; to injure fatally; to ruin;
      to destroy; as, to spoil paper; to have the crops spoiled
      by insects; to spoil the eyes by reading.
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The Collaborative International Dictionary of English v.0.48:

Spoil \Spoil\ (spoil), v. i.
   1. To practice plunder or robbery.
      [1913 Webster]

            Outlaws, which, lurking in woods, used to break
            forth to rob and spoil.               --Spenser.
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   2. To lose the valuable qualities; to be corrupted; to decay;
      as, fruit will soon spoil in warm weather.
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The Collaborative International Dictionary of English v.0.48:

Spoil \Spoil\, n. [Cf. OF. espoille, L. spolium.]
   1. That which is taken from another by violence; especially,
      the plunder taken from an enemy; pillage; booty.
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            Gentle gales,
            Fanning their odoriferous wings, dispense
            Native perfumes, and whisper whence they stole
            Those balmy spoils.                   --Milton.
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   2. Public offices and their emoluments regarded as the
      peculiar property of a successful party or faction, to be
      bestowed for its own advantage; -- commonly in the plural;
      as, to the victor belong the spoils.
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            From a principle of gratitude I adhered to the
            coalition; my vote was counted in the day of battle,
            but I was overlooked in the division of the spoil.
                                                  --Gibbon.
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   3. That which is gained by strength or effort.
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            Each science and each art his spoil.  --Bentley.
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   4. The act or practice of plundering; robbery; waste.
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            The man that hath no music in himself,
            Nor is not moved with concord of sweet sounds,
            Is fit for treason, stratagems, and spoils. --Shak.
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   5. Corruption; cause of corruption. [Archaic]
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            Villainous company hath been the spoil of me.
                                                  --Shak.
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   6. The slough, or cast skin, of a serpent or other animal.
      [Obs.] --Bacon.
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   Spoil bank, a bank formed by the earth taken from an
      excavation, as of a canal.

   The spoils system, the theory or practice of regarding
      public offices and their emoluments as so much plunder to
      be distributed among their active partisans by those who
      are chosen to responsible offices of administration.
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WordNet (r) 3.0 (2006):

spoil
    n 1: (usually plural) valuables taken by violence (especially in
         war); "to the victor belong the spoils of the enemy"
    2: the act of spoiling something by causing damage to it; "her
       spoiling my dress was deliberate" [syn: spoil, spoiling,
       spoilage]
    3: the act of stripping and taking by force [syn: spoil,
       spoliation, spoilation, despoilation, despoilment,
       despoliation]
    v 1: make a mess of, destroy or ruin; "I botched the dinner and
         we had to eat out"; "the pianist screwed up the difficult
         passage in the second movement" [syn: botch, bodge,
         bumble, fumble, botch up, muff, blow, flub,
         screw up, ball up, spoil, muck up, bungle,
         fluff, bollix, bollix up, bollocks, bollocks up,
         bobble, mishandle, louse up, foul up, mess up,
         fuck up]
    2: become unfit for consumption or use; "the meat must be eaten
       before it spoils" [syn: spoil, go bad]
    3: alter from the original [syn: corrupt, spoil]
    4: treat with excessive indulgence; "grandparents often pamper
       the children"; "Let's not mollycoddle our students!" [syn:
       pamper, featherbed, cosset, cocker, baby, coddle,
       mollycoddle, spoil, indulge]
    5: hinder or prevent (the efforts, plans, or desires) of; "What
       ultimately frustrated every challenger was Ruth's amazing
       September surge"; "foil your opponent" [syn: thwart,
       queer, spoil, scotch, foil, cross, frustrate,
       baffle, bilk]
    6: have a strong desire or urge to do something; "She is itching
       to start the project"; "He is spoiling for a fight" [syn:
       itch, spoil]
    7: destroy and strip of its possession; "The soldiers raped the
       beautiful country" [syn: rape, spoil, despoil,
       violate, plunder]
    8: make imperfect; "nothing marred her beauty" [syn: mar,
       impair, spoil, deflower, vitiate]

Moby Thesaurus II by Grady Ward, 1.0:

206 Moby Thesaurus words for "spoil":
   accommodate, acquisition, baby, baffle, balk, be after,
   be all thumbs, be desirous of, be spoiling for, blackmail, blast,
   blemish, blight, blot, blunder, blunder away, blunder into,
   blunder on, blunder upon, boggle, boodle, booty, botch, brave,
   break down, break up, bumble, bungle, butcher, canker, cater to,
   challenge, checkmate, circumvent, cocker, coddle, commit a gaffe,
   confound, confront, contravene, corrupt, cosset, counter,
   counteract, countermand, counterwork, crave, cross, crumble,
   crumble into dust, curdle, damage, dash, decay, decompose, deface,
   defeat, defile, deflorate, defy, demolish, depredate, desecrate,
   desolate, despoil, destroy, devastate, discomfit, disconcert,
   discountenance, disfigure, dish, disintegrate, disrupt, dote on,
   dysphemize, elude, fall into decay, fall to pieces, faux pas,
   favor, fester, fleece, flounder, flummox, foil, forage, foray,
   force, freeboot, frustrate, fumble, gangrene, give way to, go bad,
   go off, go to pieces, goods, grab, graft, gratify, gut, harm, haul,
   hot goods, humor, hurt, impair, indulge, injure, itch for, kill,
   knock the chocks, look a fright, look a mess, look bad, look for,
   look like hell, look something terrible, loot, lumber, mar, maraud,
   mess up, mildew, miscue, mold, molder, mollycoddle, mortify,
   moulder, much, muddle, muff, murder, necrose, nonplus, oblige,
   offend, offend the eye, outrage, pamper, perks, perplex,
   perquisite, pickings, pillage, play havoc with, please, plunder,
   pork barrel, prejudice, prey on, prize, public till, public trough,
   putrefy, putresce, queer, raid, rankle, ransack, ravage, raven,
   ravish, reive, rifle, rot, ruin, sabotage, sack, satisfy, scar,
   scotch, slip, snafu, sphacelate, spike, spoils, spoils of office,
   spoliate, spoliation, squeeze, stealings, stolen goods, stonewall,
   stumble, stump, suppurate, swag, sweep, taint, take, tarnish,
   thwart, till, trip, turn, uglify, upset, violate, vitiate, waste,
   wreck, yearn for, yield to