knock·out
ˈnäk-ˌau̇t 
1
a
: 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
(2)
c
: a blow that knocks out an opponent
2
: a sensationally striking, appealing, or attractive person or thing
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
knocked out; knocking out; knocks out
1
: to produce roughly or hastily
2
a(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
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
Recent Examples on the Web
Brenton Blanchet, People.com, 22 Mar. 2025
The 45-year-old then pulled off one of the most spectacular knockouts in boxing history in 1994, flooring Michael Moorer — 19 years his junior — with one perfect combination to claim Moorer’s two heavyweight belts.
—Greg Beacham, Chicago Tribune, 22 Mar. 2025
Tribune News Service, Orlando Sentinel, 23 July 2024
The knockout blow to the fighter, as Findeisen gleefully pointed out, was the name of the fake NFT project, SourzNFT Candies are Moundbound.
—Leo Schwartz, Fortune Crypto, 3 Feb. 2023
Brian Mazique, Forbes, 12 Mar. 2025
That perception began to turn last fall, when Hurricane Helene deluged Asheville, knocking out water and electricity for months.
—Phillip Valys, Sun Sentinel, 8 Mar. 2025
See All Example Sentences for knockout
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Noun
Ali, who was 32 at the time, faced off against the younger Foreman, then 25, for his heavyweight title in Zaire (now the Democratic Republic of Congo) — ultimately winning by knockout against the then-undefeated Foreman in the eighth round.
—Brenton Blanchet, People.com, 22 Mar. 2025
The 45-year-old then pulled off one of the most spectacular knockouts in boxing history in 1994, flooring Michael Moorer — 19 years his junior — with one perfect combination to claim Moorer’s two heavyweight belts.
—Greg Beacham, Chicago Tribune, 22 Mar. 2025
Adjective
Even if Germany beats Colombia, a knockout path of Japan then either of those would be much better than facing Spain at any point.
—Tribune News Service, Orlando Sentinel, 23 July 2024
The knockout blow to the fighter, as Findeisen gleefully pointed out, was the name of the fake NFT project, SourzNFT Candies are Moundbound.
—Leo Schwartz, Fortune Crypto, 3 Feb. 2023
Verb
He was knocked out in the first round by Liam Paro at 140 pounds in October 2022.
—Brian Mazique, Forbes, 12 Mar. 2025
That perception began to turn last fall, when Hurricane Helene deluged Asheville, knocking out water and electricity for months.
—Phillip Valys, Sun Sentinel, 8 Mar. 2025
See All Example Sentences for knockout
Cite this Entry
“Knockout.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/knockout. Accessed 25 Mar. 2025.
Copy CitationKids Definition
knockout
1 of 2 noun
knock·out
ˈnäk-ˌau̇t
1
: the act of knocking out : the condition of being knocked out
2
: something or someone very striking or attractive
knockout
adjective
knock out
2 of 2 verbˈnäk-ˈau̇t,
näk-ˈau̇t
: to make unconscious
Medical Definition
knockout
adjective
knock·out
ˈnäk-ˌau̇t
: 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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