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
Synonyms
Noun
- babe [slang]
- beauty
- beauty queen
- cookie
- cooky
- cutie
- cutey
- dolly bird [British]
- enchantress
- eyeful
- fox
- goddess
- honey
- queen
- stunner
Adjective
- aesthetic
- esthetic
- aesthetical
- esthetical
- attractive
- beauteous
- beautiful
- bonny [chiefly British]
- bonnie
- comely
- cute
- drop-dead
- fair
- fetching
- good
- good-looking
- goodly
- gorgeous
- handsome
- likely
- lovely
- lovesome
- pretty
- ravishing
- seemly
- sightly
- stunning
- taking
- well-favored
Verb
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
Glynn A. Hill, Washington Post, 6 July 2024
This year’s tournament, which ends July 14, isn’t even halfway over, and the most exciting part — the knockout stage — has yet to begin.
—Leah Asmelash, CNN, 2 July 2024
Leo Schwartz, Fortune Crypto, 3 Feb. 2023
Addison Rae added to the ever-growing list of knockout vintage Y2K, donning a wrap skirt from Roberto Cavalli’s spring 2000 collection.
—André-Naquian Wheeler, Vogue, 28 Jan. 2023
Ella Nilsen, CNN, 12 July 2024
In Galveston County on Tuesday, someone who depended on medical oxygen died after electricity was knocked out, a generator failed, and the batteries on a portable oxygen concentrator went dead, state Sen. Mayes Middleton, R-Galveston, said at a news conference.
—Patrick Smith, NBC News, 10 July 2024
See all Example Sentences for knockout 
Noun
The Three Lions topped Group C with a win over Serbia and draws against Denmark and Slovenia, but the comeback win over Slovakia to start the knockout stage showed a new spark of energy.
—Glynn A. Hill, Washington Post, 6 July 2024
This year’s tournament, which ends July 14, isn’t even halfway over, and the most exciting part — the knockout stage — has yet to begin.
—Leah Asmelash, CNN, 2 July 2024
Adjective
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
Addison Rae added to the ever-growing list of knockout vintage Y2K, donning a wrap skirt from Roberto Cavalli’s spring 2000 collection.
—André-Naquian Wheeler, Vogue, 28 Jan. 2023
Verb
Then Category 1 Beryl swept through in an unusually early start to hurricane season, knocking out power for more than 2 million customers.
—Ella Nilsen, CNN, 12 July 2024
In Galveston County on Tuesday, someone who depended on medical oxygen died after electricity was knocked out, a generator failed, and the batteries on a portable oxygen concentrator went dead, state Sen. Mayes Middleton, R-Galveston, said at a news conference.
—Patrick Smith, NBC News, 10 July 2024
See all Example Sentences for knockout
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'knockout.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near knockout
Cite this Entry
“Knockout.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/knockout. Accessed 20 Jul. 2024.
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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