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 Some teams may see advancing to the eight-team knockout round and playing additional games as a detriment, leading to a new kind of tanking., "The in-season tournament idea is a flagrantly bad idea. Unlike NBA players, it simply doesn’t fly.," 1 Dec. 2019 Friday represents an absolutely crucial game for the USMNT whose path to advance to the knockout stage of the inaugural Nations League is now fairly clear cut, but not at all easy. Tim Brown, oregonlive, "USMNT vs Canada soccer: Live updates, score, TV channel, how to watch free live stream online (CONCACAF Nations League)," 15 Nov. 2019 That stung – but the tournament's 24-team format meant that four out of six teams who finished third in their group would qualify for the knockouts., "Scotland 3-3 Argentina: High VARma in Paris as World Cup Underdogs Knock Each Other Out," 31 Oct. 2019 But at this point, kismet may matter as much as Ks for a team that has won six of eight playoff games since facing a 3-1, eighth-inning deficit in the NL knockout match against Milwaukee. Gabe Lacques, USA TODAY, "Nationals look unbeatable against Cardinals in NLCS: 'There's this weird feeling'," 13 Oct. 2019 Head coach Jamie Joseph pointed out on Friday, when he was riled by reports that Japan would get an easy ride to the knockouts if Sunday’s game was cancelled, that his team was just as desperate as Scotland to play. San Diego Union-Tribune, "As Japan braces for typhoon, rugby squad trains in the rain," 12 Oct. 2019 Riddell lets Mullarkey back up and looks to get the knockout on the feet. Todd Martin, Los Angeles Times, "UFC 243 recap: Israel Adesanya knocks out Robert Whittaker in second round," 5 Oct. 2019 Curaçao advanced to the knockout round after finishing second in Group C. The United States won the 2017 CONCACAF Gold Cup with a 2-1 win over Jamaica. Jamie Goldberg,, "USA vs. Curacao in 2019 CONCACAF Gold Cup quarterfinal: Live updates, TV channel, how to watch online," 30 June 2019 Reiss allowed the knockout to be scored by the judges but docked Paul two points, despite not being warned for the fouls, the outlet reported. Eric Todisco,, "YouTube Stars Logan Paul and KSI Face Off in Boxing Match — See Who Won the Showdown," 11 Nov. 2019

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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Time Traveler for knockout

Time Traveler

The first known use of knockout was in 1818

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Statistics for knockout

Last Updated

8 Dec 2019

Cite this Entry

“Knockout.” The Dictionary, Merriam-Webster Inc., Accessed 15 December 2019.

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More Definitions for knockout


How to pronounce knock out (audio)

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

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Comments on knockout

What made you want to look up knockout? Please tell us where you read or heard it (including the quote, if possible).


delight or enjoyment

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