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 Fresh off his knockout of former NBA player Nate Robinson, Paul is looking to challenge one of the most dangerous fighters in UFC history. Allen Kim, CNN, "YouTuber Jake Paul offers UFC fighter Conor McGregor $50 million to box him," 15 Dec. 2020 Style points are going to matter this season and on paper, the victory will go down as a three-score knockout. John Canzano, oregonlive, "Canzano: Oregon Ducks opener was a survive-and-advance victory over Stanford," 8 Nov. 2020 But a win against Inter Milan on Wednesday gives the team and its manager Zinedine Zidane breathing space and, more importantly, qualification to the Champions League knockout stages. Calum Trenaman, CNN, "Ten years on from humiliating Real Madrid 5-0, Barcelona is a club in turmoil," 28 Nov. 2020 Last season's single-elimination, knockout format (vs. the home-and-home series used in previous seasons) was the highest-scoring postseason in league history at 4.1 goals a game. Jim Reineking, USA TODAY, "MLS playoff story lines to follow: Philadelphia Union, Seattle Sounders among key teams in 18-team field," 9 Nov. 2020 As Fortune‘s David Meyer reports, Delivery Hero really delivered for investors last quarter, reporting knockout sales and profits, and improved its guidance. Bernhard Warner, Fortune, "After Wednesday’s monster sell-off, global markets remain choppy ahead of a Big Tech earnings bonanza," 29 Oct. 2020 With the lead trimmed to 19-14 late in the fourth quarter, the Ravens had a chance to get the ball back and, against all odds, deliver a 12th-round, knockout blow. Jonas Shaffer,, "Short-handed Ravens fall to Steelers, 19-14, are eliminated from AFC North title contention," 2 Dec. 2020 Contestants Carter Rubin and Chloé Hogan made coaches Kelly Clarkson and Gwen Stefani emotional during their recent knockout round performance. Kayla Keegan, Good Housekeeping, "'The Voice' Stars Gwen Stefani and Kelly Clarkson Tear Up During Emotional Knockout Moment," 29 Nov. 2020 It’s not a knockout, but the actors frequently are. Mark Olsen Staff Writer, Los Angeles Times, "Indie Focus: A dazzling ‘Ma Rainey’s Black Bottom’," 25 Nov. 2020 Recent Examples on the Web: Adjective Rangers haven’t lost a game in any competition this season, having won their five preseason games, their only Scottish Cup match and three Europa League qualifiers before going 4-0-2 in the group stage games to advance to the knockout phase. Kevin Baxter, Los Angeles Times, "Soccer newsletter: CONCACAF Champions League resumes play this week," 15 Dec. 2020 The company posted another round of knockout earnings and raised its forecast Thursday, showing that a surge in demand caused by the coronavirus pandemic isn't wearing off. Michelle Toh, CNN, "Nintendo profits jump 200% as Switch sales continue to sizzle," 5 Nov. 2020 The object of his affection was a knockout Romanesque Revival showplace built in 1885 as a two-story office for the William Ulmer Brewery, which stood next door and survives today as a vacant shell adorned with a colorful wash of graffiti. John Freeman Gill, New York Times, "In Brooklyn, a Ghost of Breweries Past," 30 Oct. 2020 Well, when Pro Picks takes them in the knockout pool. Barry Wilner, Star Tribune, "NFC Least leader could come out of Giants-Eagles game," 21 Oct. 2020 Not to mention Moore gave political activism a knockout finish in the process. Christian Allaire, Vogue, "Julianne Moore Encourages Voting in the Most Glamorous Way Possible," 5 Oct. 2020 Charisma Osborne got the Bruins (4-1, 2-1 Pac-12) started with 13 of her 18 points in the first quarter, then Onyenwere delivered the knockout punch with 14 points in the third quarter as UCLA took a 12-point halftime lead and expanded it to 27. Thuc Nhi Nguyen Staff Writer, Los Angeles Times, "Michaela Onyenwere and Charisma Osborne push UCLA to victory over USC," 13 Dec. 2020 There are growing concerns that a nasty second wave of infections could be a knockout blow for the economy. Katherine Dunn, Fortune, "As COVID spreads across Europe, a weary continent goes back into lockdown," 7 Nov. 2020 Biden doesn't have to win Florida to claim the presidency, but a victory there early on election night would effectively deliver a knockout blow to the Trump campaign. Emily Larsen, Washington Examiner, "Trump and Biden in Tampa: Too hot to handle versus rained-out disappointment," 29 Oct. 2020

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

29 Dec 2020

Cite this Entry

“Knockout.” Dictionary, Merriam-Webster, Accessed 16 Jan. 2021.

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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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