Knock-out, a. That knocks out; characterized by knocking out; as, a knock-out blow; a knock-out key for knocking out a drill from a collet.
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  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. [wns=1]
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  knockout
       adj : very strong or vigorous; "strong winds"; "a hard left to the
             chin"; "a knockout punch"; "a severe blow" [syn: hard,
              severe]
       n 1: a very attractive or seductive looking woman [syn: smasher,
             stunner, beauty, ravisher, sweetheart, peach,
             lulu, looker, mantrap, dish]
       2: a blow that renders the opponent unconscious [syn: KO]