knock·​out | \ ˈnäk-ˌau̇t How to pronounce knockout (audio) \

Definition of knockout

 (Entry 1 of 3)

1a : the act of knocking out : the condition of being knocked out
b(1) : the termination of a boxing match when one boxer has been knocked down and is unable to rise and resume boxing within a specified time
c : a blow that knocks out an opponent
2 : a sensationally striking, appealing, or attractive person or thing



Definition of knockout (Entry 2 of 3)

1 : causing a knockout a knockout blow
2 : sensationally striking, appealing, or attractive a knockout dress
3 : having all or part of a gene eliminated or inactivated by genetic engineering knockout mice predisposed to diabetes mellitus

knock out

knocked out; knocking out; knocks out

Definition of knock out (Entry 3 of 3)

transitive verb

1 : to produce roughly or hastily
2a(1) : to defeat (a boxing opponent) by a knockout
(2) : to make unconscious the drug knocked him out
b : to make inoperative or useless electricity was knocked out by the storm
c : to get rid of : eliminate knocked out illegal gambling
3 : to tire out : exhaust knocked themselves out with work
4 : to cause (an opposing pitcher) to be removed from a baseball game by a batting rally

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Examples of knockout in a Sentence

Noun He won the match by a knockout. He scored a knockout in the fourth round. She's a real knockout in that dress. Adjective The Wimbledon tennis tournament is a knockout competition. a knockout sports car that's the talk of the neighborhood Verb the entire staff knocked itself out getting the project finished on time
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Recent Examples on the Web: Noun Most fans predicted the same result: a McGregor knockout. Jordan Mendoza, USA TODAY, 10 July 2021 With neither side able to find a winning goal, the tie would go to extra time, meaning that every knockout match that Spain had played would last 120 minutes. Matias Grez, CNN, 6 July 2021 Both players are now preparing for their knockout matches this weekend — Gallese and Peru will face Paraguay on Friday, while Méndez and Ecuador will face Argentina on Saturday. Julia Poe,, 30 June 2021 The way the knockout draw has fallen means whichever team wins tomorrow has, in theory, an easier path to the final. Robert Kidd, Forbes, 28 June 2021 The singer welcomed starved theatergoers back to claim their seats on the Great White Way with a revival of his Tony-winning knockout. Dan Morrissey,, 27 June 2021 The knockout rounds, starting with Austria on Saturday, are an opportunity to build his case. New York Times, 25 June 2021 The bouts never end with a knockout in which one of the two combatants blocks or unfollows the other. Stephen Humphries, The Christian Science Monitor, 28 May 2021 The Showtime analyst is eager to see whether Davis’ stalking style, which has earned him comparisons to a miniature Mike Tyson, will produce a knockout against such an opponent. Childs Walker,, 24 June 2021 Recent Examples on the Web: Adjective However, the knockout artist has insisted on fighting in Las Vegas, once in an empty arena during the pandemic and against last month in a modest 4,500-seat theater. Los Angeles Times, 12 July 2021 Both gold medal teams from the 2016 Olympics in Rio de Janeiro finished fourth in pool play before winning three straight matches in the knockout round to claim gold. Josh Dubow, Star Tribune, 3 July 2021 And with two losses and only one game left to play in that round, the Danes seemed to have little chance of advancing to the knockout round. Clint Smith, The Atlantic, 2 July 2021 The sportswear giant delivered knockout top-line results after the bell yesterday, boosted by impressive e-commerce and North American sales. Bernhard Warner, Fortune, 25 June 2021 Both fighters are coming off knockout victories at the Alamodome on Halloween night. John Whisler, San Antonio Express-News, 25 June 2021 The Epic Games Store’s appropriately named Epic Mega Sale continues to roll on, and today the Steam rival revealed a truly knockout freebie to lure you into virtual aisles. Brad Chacos, PCWorld, 10 June 2021 Each can win only by knockout, technical knockout or disqualification. Mark Heim |, al, 6 June 2021 After 40 targets the knockout format had narrowed the competition to two: Bernau and Alessandra Perilli, 33, of San Marino. Paul A. Smith, Milwaukee Journal Sentinel, 15 May 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'knockout.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of knockout


1887, in the meaning defined at sense 1a


1818, in the meaning defined at sense 1


1856, in the meaning defined at sense 1

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Learn More About knockout

Time Traveler for knockout

Time Traveler

The first known use of knockout was in 1818

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Statistics for knockout

Last Updated

15 Jul 2021

Cite this Entry

“Knockout.” Dictionary, Merriam-Webster, Accessed 24 Jul. 2021.

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More Definitions for knockout



English Language Learners Definition of knockout

 (Entry 1 of 2)

: an occurrence in which a boxing match ends when a fighter has been knocked down by a punch and is unable to start fighting again before 10 seconds have passed
informal : a very attractive or appealing person or thing



English Language Learners Definition of knockout (Entry 2 of 2)

: causing someone to become unconscious
informal : extremely attractive or appealing
British, of a contest or competition : designed so that winning teams or players continue to play and losing teams or players do not


knock·​out | \ ˈnäk-ˌau̇t How to pronounce knockout (audio) \

Medical Definition of knockout

: having all or part of a gene eliminated or inactivated by genetic engineering knockout mice predisposed to diabetes mellitus serve as animal models in the study of human diabetes

More from Merriam-Webster on knockout

Nglish: Translation of knockout for Spanish Speakers

Britannica English: Translation of knockout for Arabic Speakers Encyclopedia article about knockout


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