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Synonyms

knockout

American  
[nok-out] / ˈnɒkˌaʊt /

noun

knockouts plural
  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

  1. that knocks out.

    the knockout punch.

knockout British  
/ ˈnɒkˌaʊt /

noun

  1. the act of rendering unconscious

  2. a blow that renders an opponent unconscious

    1. a competition in which competitors are eliminated progressively

    2. ( as modifier )

      a knockout contest

  3. a series of absurd invented games, esp obstacle races, involving physical effort or skill

  4. informal a person or thing that is overwhelmingly impressive or attractive

    she's a knockout

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. to render unconscious, esp by a blow

  2. boxing to defeat (an opponent) by a knockout

  3. to destroy, damage, or injure badly

  4. to eliminate, esp in a knockout competition

  5. informal to overwhelm or amaze, esp with admiration or favourable reaction

    I was knocked out by that new song

  6. to remove the ashes from (one's pipe) by tapping

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Noun Inflected Forms

Etymology

Origin of knockout

1810–20; 1935–40 knockout for def. 4; noun, adj. use of verb phrase knock out

Explanation

In the sport of boxing, a knockout is a blow that sends one of the boxers to the mat, unable to continue fighting. If you are down and can't rise before the ref counts to ten, consider it a knockout. In full-contact fighting sports, including boxing, karate, and kickboxing, the ultimate goal is a match-winning knockout of the opponent. Not all boxing matches end this way, but a knockout is the most exciting (and dangerous) way for a match to end. This word is also used to mean "gorgeous person," so if someone tells you you're a knockout, you can be sure they mean it as a compliment.

Keep Reading on Vocabulary.com

Vocabulary lists containing knockout

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

England's place in the knockout stages of the World Cup has been confirmed before they face Panama in their final group game on Saturday.

From BBC • Jun. 27, 2026

Then the United States took care of Australia 2-0 on June 19 without Pulisic to secure their place in knockout play.

From Los Angeles Times • Jun. 26, 2026

It is a debate that will rumble on into the summer, with Scotland's chances of knockout progression now rated at about 5%.

From BBC • Jun. 26, 2026

But it will need him in the knockout stage.

From Los Angeles Times • Jun. 26, 2026

Probably a knockdown or a knockout, he thought; maybe the brash kid had made good his boast.

From "145th Street: Short Stories" by Walter Dean Myers

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