Synonyms for Spoil:

n.

adopt, carry, return, put in, ballot, blackball, reelect, elect, abstain. cost, offset, overshadow, disgrace, injure, destroy, harm, loose on, cancel out, neutralize. curdle, go off, biodegrade, perish, deteriorate, fester, thrive, mold, better. overindulge, cater. havoc, Spoliate, give, harrow. act (noun)
spoiling, spoilage.
spoil (noun)
bollix, corrupt, blow, botch, muck up, spoilage, itch, featherbed, fuck up, vitiate, indulge, cocker, ball up, despoilment, mess up, impair, baby, cross, spoiling, mollycoddle, thwart, bollix up, coddle, go bad, deflower, botch up, louse up, screw up, bungle, despoilation, foil, baffle, spoilation, bumble, bobble, cosset, bilk, bollocks up, despoil, mishandle, scotch, fumble, spoliation, frustrate, foul up, pamper, despoliation, bollocks, violate, fluff, plunder, mar, flub.

v.

abuse (verb)
ruin, violate, corrupt, mishandle.
blast (verb)
torpedo, shatter.
blight (verb)
decay, frustrate, foul up.
change (verb)
corrupt.
damage (verb)
ravage, pillage, ruin, waste, despoil, rend, Depredate, wreak havoc, vandalize, wreck, lay waste, ransack.
disintegrate (verb)
anatomize, rot, break, crumble, disintegrate, shatter, dissolve, decompose, mortify, putrefy, turn, degenerate, dissect, decay, rupture.
rape (verb)
ravish, violate, defile, deflower.
ruin, hurt (verb)
mess up.
spoil (verb)
harm, Spoliate, disfigure, deface, destroy, despoil, disgrace, plunder, deteriorate, putrefy, Depredate, go off, blemish, disintegrate, pamper, rot, mollycoddle, impair, pillage, waste, turn, demolish, crumble, overindulge, cosset, tarnish, decompose, injure, wreck, mar, curdle, damage, vitiate, muck up, go bad, coddle, undo, smash, taint, defile, ravage.

Other synonyms:

elect, harm, blackball, loose on, cancel out, overindulge, Spoliate, offset, gum up, fuss over, overshadow, reelect, adopt, put in. boggle, cost, torpedo, neutralize, carry, cater, return, harrow, ballot. demolish, destroy, abstain, bankrupt. deteriorate. muddle, smash, undo. finish. sink. blemish
scar.
defeat
neutralize.
deform
flaw.
deteriorate
sink.
foul-up
foul up.
mess-up
mess up.
pamper
pamper, mollycoddle.
ruin
ruin.
waste
waste.

Usage examples for spoil

  1. " Because you spoil sport. – King of the Castle by George Manville Fenn
  2. Probably he wanted to burn out my motor, and spoil it. – Tom Swift and his Electric Runabout or, The Speediest Car on the Road by Victor Appleton
  3. Miss Jenny Ann was already dreadfully nervous about them and, besides, it would spoil Madge's home coming. – Madge Morton, Captain of the Merry Maid by Amy D. V. Chalmers