knockout

• POS: Noun, Verb (usu participle)
• HYPHEN: knock=out

CIDE DICTIONARY

knockout, n. 

•  Act of knocking out, or state of being knocked out; the act of rendering a person unconscious by a blow.  [Webster 1913 Suppl.]
•  a blow which causes a person to become unconscious.  [WordNet 1.5]
•  the winning of a boxing contest by rendering the opponent unable to stand for a specified period, usually a count of ten; -- in contrast to a win by a decision; as, Muhammed Ali won by a knockout in the first round.  [WordNet 1.5]
•  a strikingly beautiful woman.  [PJC]

OXFORD DICTIONARY

knockout, n.
1 the act of making unconscious by a blow.
2 Boxing etc. a blow that knocks an opponent out.
3 a competition in which the loser in each round is eliminated (also attrib.: a knockout round).
4 colloq. an outstanding or irresistible person or thing.

Idiom

knockout drops a drug added to a drink to cause unconsciousness.

THESAURUS

knockout

Cadmean victory, KO, Miss America, Pyrrhic victory, ace, ascendancy, bathing beauty, beau ideal, beaut, beauty, beauty contest winner, beauty queen, belle, blackout, bunny, catalepsy, catatonia, catatony, championship, charmer, clincher, coma, conquest, corker, coup de grace, cover girl, crackerjack, crusher, daisy, dandy, darb, dazzler, death stroke, deathblow, dilly, dream, easy victory, enchantress, end-all, ender, eyeful, faint, final stroke, finisher, finishing stroke, grand slam, grayout, great beauty, hit, honey, humdinger, kayo, kayo punch, killer-diller, knockout blow, lady fair, landslide, landslide victory, last dab, lipothymia, lipothymy, lollapaloosa, looker, lovely, lulu, mastery, model, moral victory, nirvana, nirvana principle, nothingness, oblivion, obliviousness, paragon, peach, picnic, pinup, pinup girl, pip, pippin, pushover, pussycat, quietus, raving beauty, reigning beauty, runaway victory, semiconsciousness, sensation, senselessness, settler, sex kitten, sleep, slick chick, smash, smash hit, sockdolager, stopper, stunner, stupor, subdual, subduing, success, sweetheart, swoon, syncope, the nuts, total victory, triumph, unconsciousness, victory, walkaway, walkover, whiz, win, winner, winning, winning streak