Englishundo
verb
1 Gerald undid another button of his vest:
unfasten, unbutton, unhook, untie, unlace;
unbind, unfetter, unshackle, unmanacle, unbridle, unlock, unbolt, uncouple, unhitch, unlink, unclick, loosen, loose, disentangle, disentwine, extricate, release, detach, free, set free, liberate, open, unseal, unwrap, let out;
disconnect, disjoin, disengage, disunite, separate.
▷antonyms fasten, do up.
2 the measures undo many of the agreements that were struck in 1999:
revoke, overrule, overturn, repeal, rescind, reverse, retract, take back, rule against, disallow, veto, countermand, cancel, annul, nullify, render null and void, invalidate, render invalid, negate, abrogate, disestablish, make ineffective, set aside, do away with, wipe out, bring to an end;
Law avoid, vacate;
archaic recall;
rare disannul.
▷antonyms ratify.
3 the action of one individual can undo much of the good work done by others:
ruin, undermine, put an end to, put at risk, subvert, overturn, topple, scupper, scotch, sabotage, spoil, mess up, make a mess of, quash, squelch, crush, harm, cripple, impair, mar, destroy, devastate, play havoc with, wreck, smash, shatter, annihilate, eradicate, obliterate, defeat;
cancel out, neutralize, render ineffective;
thwart, upset, foil, frustrate, hamper, hinder, obstruct;
informal botch, blow, put the kibosh on, foul up, muck up, louse up, blow a hole in, do for;
British, informal cock up, throw a spanner in the works of;
North American, informal rain on someone's parade, throw a monkey wrench in the works of;
vulgar slang fuck up;
British, vulgar slang bugger up, balls up;
archaic bring to naught.
▷antonyms further, enhance, help.