knockout /(?)/

knock·out

knockout

n.
  1. Act of knocking out, or state of being knocked out; the act of rendering a person unconscious by a blow.
  2. a blow which causes a person to become unconscious.
  3. 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. (Boxing)
  4. a strikingly beautiful woman. [Informal]