Undo

• POS: Verb (usu participle)
• HYPHEN: un=do

CIDE DICTIONARY

Undo, v. t. [AS. undn. See 1st Un-, and Do to perform.].

•  To reverse, as what has been done; to annul; to bring to naught.  [1913 Webster]

  "What's done can not be undone."  [1913 Webster]

  "To-morrow, ere the setting sun,
  She 'd all undo that she had done."  [1913 Webster]
•  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.  Tennyson.  [1913 Webster]

  "Pray you, undo this button."  [1913 Webster]

  "She took the spindle, and undoing the thread gradually, measured it."  [1913 Webster]
•  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.  [1913 Webster]

  "That quaffing and drinking will undo you,"  [1913 Webster]

OXFORD DICTIONARY

Undo, v.tr. (3rd sing. present -does; past -did; past part. -done)
1 a unfasten or untie (a coat, button, parcel, etc.). b unfasten the clothing of (a person).
2 annul, cancel (cannot undo the past).
3 ruin the prospects, reputation, or morals of.

Etymology

OE undon (as UN-(2), DO(1))

THESAURUS

Undo

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

ROGET THESAURUS

Undo

Disjunction

VB be disjoined, come off, fall off, come to pieces, fall to pieces, peel off, get loose, disjoin, disconnect, disengage, disunite, dissociate, dispair, divorce, part, dispart, detach, separate, cut off, rescind, segregate, set apart, keep apart, insulate, isolate, throw out of gear, cut adrift, loose, unloose, undo, unbind, unchain, unlock, unpack, unravel, disentangle, set free, sunder, divide, subdivide, sever, dissever, abscind, circumcise, cut, incide, incise, saw, snip, nib, nip, cleave, rive, rend, slit, split, splinter, chip, crack, snap, break, tear, burst, rend, rend asunder, rend in twain, wrench, rupture, shatter, shiver, cranch, crunch, craunch, chop, cut up, rip up, hack, hew, slash, whittle, haggle, hackle, discind, lacerate, scamble, mangle, gash, hash, slice, cut up, carve, dissect, anatomize, dislimb, take to pieces, pull to pieces, pick to pieces, tear to pieces, tear to tatters, tear piecemeal, tear limb from limb, divellicate, skin, disintegrate, dismember, disbranch, disband, disperse, dislocate, disjoint, break up, mince, comminute, apportion, part, part company, separate, leave.

Inaction

VB not do, not act, not attempt, be inactive, abstain from doing, do nothing, hold, spare, not stir, not move, not lift a finger, not lift a foot, not lift a peg, fold one's arms, fold one's hands, leave alone, let alone, let be, let pass, let things take their course, let it have its way, let well alone, let well enough alone, quieta non movere, stare super antiquas vias, rest and be thankful, live and let live, lie rest upon one's oars, laisser aller, faire, stand aloof, refrain, keep oneself from doing, remit one's efforts, relax one's efforts, desist, stop, pause, wait, lie in wait, bide one's time, take time, tide it over, cool one's heels, kick one's heels, while away the time, while away tedious hours, pass the time, fill up the time, beguile the time, talk against time, let the grass grow under one's feet, waste time, lie by, lie on the shelf, lie in ordinary, lie idle, lie to, lie fallow, keep quiet, slug, have nothing to do, whistle for want of thought, undo, do away with, take down, take to pieces, destroy.

Reversion

VB revert, turn back, regress, relapse, recoil, retreat, restore, undo, unmake, turn the tide, roll back the tide, turn the scale, tip the scale.

Destruction

VB be destroyed, perish, fall to the ground, tumble, topple, go to pieces, fall to pieces, break up, crumble to dust, go to the dogs, go to the wall, go to smash, go to shivers, go to wreck, go to pot, go to wrack and ruin, go by the board, go all to smash, be all over, be all up, be all with, totter to its fall, destroy, do away with, make away with, nullify, annual, sacrifice, demolish, tear up, overturn, overthrow, overwhelm, upset, subvert, put an end to, seal the doom of, do in, do for, dish, undo, break up, cut up, break down, cut down, pull down, mow down, blow down, beat down, suppress, quash, put down, do a job on, cut short, take off, blot out, dispel, dissipate, dissolve, consume, smash, crash, quell, squash, squelch, crumple up, shatter, shiver, batter to pieces, tear to pieces, crush to pieces, cut to pieces, shake to pieces, pull to pieces, pick to pieces, laniate, nip, tear to rags, tear to tatters, crush to atoms, knock to atoms, ruin, strike out, throw over, knock down over, fell, sink, swamp, scuttle, wreck, shipwreck, engulf, ingulf, submerge, lay in ashes, lay in ruins, sweep away, erase, wipe out, expunge, raze, level with the dust, level with the ground, waste, atomize, vaporize, deal destruction, desolate, devastate, lay waste, ravage gut, disorganize, dismantle, devour, swallow up, sap, mine, blast, bomb, blow to smithereens, drop the big one, confound, exterminate, extinguish, quench, annihilate, snuff out, put out, stamp out, trample out, lay in the dust, trample in the dust, prostrate, tread under foot, crush under foot, trample under foot, lay the ax to the root of, make short work of, make clean sweep of, make mincemeat of, cut up root and branch, chop into pieces, cut into ribbons, fling to the winds, scatter to the winds, throw overboard, strike at the root of, sap the foundations of, spring a mine, blow up, ravage with fire and sword, cast to the dogs, eradicate.

Counteraction

VB counteract, run counter, clash, cross, interfere with, conflict with, contravene, jostle, go against, run against, beat against, militate against, stultify, antagonize, block, oppose, traverse, withstand, hinder, repress, react, undo, neutralize, counterpoise, overpoise.