1. (v. t.) To reverse, as what has been done; to annul; to bring to naught.

2. (v. t.) To loose; to open; to take to piece; to unfasten; to untie; hence, to unravel; to solve; as, to undo a knot; to undo a puzzling question; to undo a riddle.

3. (v. t.) To bring to poverty; to impoverish; to ruin, as in reputation, morals, hopes, or the like; as, many are undone by unavoidable losses, but more undo themselves by vices and dissipation, or by indolence.

KO abate abolish abrogate annihilate annul answer atomize bare beat beat all hollow beat hollow best bottom break to pieces bring down bring to naught bring to nothing buffer cancel cancel out cast off clear clear up cleave come to nothing cook counterbalance crack crush dash debauch debug decimate decipher decode defeat demolish demoralize deobstruct destroy detach disassemble disclose disengage disentangle dish disintegrate dismantle divine do do for do in doff dope dope out douse drop drub explain expose fathom figure out find out find the answer find the solution fix fragment free frustrate get get right guess guess right have have it hide hit it hors de combat interpret invalidate knock down knock out lambaste lather liberate lick loose loosen make mincemeat of make out manifest negate negativate negative neutralize nullify offset ope open open the lock outclass outdo outfight outfox outgeneral outmaneuver outpoint outreach outrun outsail outshine outsmart overcome overreach patefy pick to pieces plumb prostrate psych psych out pull in pieces pull to pieces pulverize put put off puzzle out quash ravel ravel out raze reduce to rubble release remove rend repeal rescind resolve reveal reverse revoke riddle ruin scuttle settle shake shatter shoot down sink skin skin alive slip out of smash solve sort out split step out of stultify sunder take apart take off tear apart tear to pieces tear to shreds tear to tatters thrash throw off thwart torpedo total trim triumph over trounce unbar unbind unblock unbolt unbrace unbuckle unbuild unbutton uncase unchain unclasp unclench unclog unclutch uncork uncover uncurtain undrape unfasten unfetter unfold unfoul unglue unhook unlace unlatch unleash unlock unloose unloosen unmake unman unnerve unplug unravel unriddle unroll unscramble unseal unsheathe unshut unsnap unstick unstop unstrap unstring untangle untie untwist unveil unweave unwrap unzip upset vitiate void weigh anchor whip work work out worst wrack wrack up wreck