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


He won the match by a knockout. He scored a knockout in the fourth round. She's a real knockout in that dress.


The Wimbledon tennis tournament is a knockout competition. a knockout sports car that's the talk of the neighborhood


the entire staff knocked itself out getting the project finished on time
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Recent Examples on the Web: Noun

And Rapinoe has scored every goal for the United States during the knockout rounds: two on Tuesday, against Spain, and two on Friday, against France. Louisa Thomas, The New Yorker, "World Cup 2019: Megan Rapinoe Commands the Stage," 29 June 2019 Four of FC Cincinnati's regular contributors have advanced to the knockout rounds of the CONCACAF Gold Cup. , Cincinnati Enquirer,, "FC Cincinnati notebook: Rookie Logan Gdula back in the fold," 26 June 2019 Liverpool had to go through Napoli in the group stage last season en route to the knockout rounds, requiring a 1-0 win over Carlo Ancelotti's side on the final day of group play just to secure its place in the last 16. Luis Miguel Echegaray,, "LIVE: Liverpool Begins Champions League Title Defense vs. Napoli," 17 Sep. 2019 Maybe the knockout round of this World Cup can be a salve as Brown suggests. Marc Stein, New York Times, "For Gregg Popovich, the FIBA World Cup Is Personal," 10 Sep. 2019 Meanwhile, there are some surprise qualifiers for the knockout round of the World Cup, such as the Dominican Republic, Puerto Rico, and Venezuela. Gary Washburn,, "Celtics coach Brad Stevens will have plenty of choices with new-look roster," 7 Sep. 2019 But wait, there’s more math. Because after playing a 34-game regular season to eliminate just 10 of 24 teams, six more will go out in 90 minutes in the first knockout-round games. Kevin Baxter, Los Angeles Times, "Soccer! Draw between Galaxy and LAFC left neither team satisfied," 27 Aug. 2019 Competitors compete in two round robin groups and knockout rounds to be crowned the WTA champion. Ben Church, CNN, "Women's tennis tournament offers historic $4.75 million prize money to winner," 1 Aug. 2019 Teams like Spain and Italy, going into the knockout rounds, had good performances. Time, "Megan Rapinoe on Equal Pay, World Cup Celebrations and Trump," 10 July 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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Statistics for knockout

Last Updated

13 Oct 2019

Look-up Popularity

Time Traveler for knockout

The first known use of knockout was in 1818

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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

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