'knockout' definitions:

Definition of 'knockout'

From: WordNet
adjective
Very strong or vigorous; "strong winds"; "a hard left to the chin"; "a knockout punch"; "a severe blow" [syn: hard, knockout, severe]
noun
A very attractive or seductive looking woman [syn: smasher, stunner, knockout, beauty, ravisher, sweetheart, peach, lulu, looker, mantrap, dish]
noun
A blow that renders the opponent unconscious [syn: knockout, KO, kayo]

Definition of 'knockout'

From: GCIDE
  • knockout \knock"out`\, knock-out \knock"-out`\, n. Act of knocking out, or state of being knocked out; the act of rendering a person unconscious by a blow. [WordNet sense 1] [Webster 1913 Suppl. + WordNet 1.5]
  • 2. a blow which causes a person to become unconscious.
  • Syn: knockout blow, knockout punch. [WordNet 1.5]
  • 3. (Boxing) 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]
  • 4. a strikingly beautiful woman. [Informal] [PJC] knockout drops

Synonyms of 'knockout'

From: Moby Thesaurus