knockout

noun

1. an act or instance of knocking out.
2. the state or fact of being knocked out.
3. a knockout blow.
4. Informal. a person or thing overwhelmingly attractive, appealing, or successful.
5. a panel in a casing, can, or box, especially of metal or plastic, so designed that it can readily be removed, as by punching, hammering, or cutting, to provide an opening into the interior: a knockout in a junction box.
6. Machinery. a device for knocking something loose, as finished work from a lathe chuck.

adjective

7. that knocks out: the knockout punch.

noun

1. the act of rendering unconscious
2. a blow that renders an opponent unconscious
3. 1. a competition in which competitors are eliminated progressively
   2. (as modifier)a knockout contest
4. a series of absurd invented games, esp obstacle races, involving physical effort or skill
5. informal a person or thing that is overwhelmingly impressive or attractiveshe’s a knockout

verb knock out (tr, adverb)

6. to render unconscious, esp by a blow
7. boxing to defeat (an opponent) by a knockout
8. to destroy, damage, or injure badly
9. to eliminate, esp in a knockout competition
10. informal to overwhelm or amaze, esp with admiration or favourable reactionI was knocked out by that new song
11. to remove the ashes from (one’s pipe) by tapping