knockout

1 of 3

noun

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)

: technical knockout

c

: a blow that knocks out an opponent

2

: a sensationally striking, appealing, or attractive person or thing

knockout

2 of 3

adjective

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

3 of 3

verb

knocked out; knocking out; knocks out

transitive verb

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

• daze
• trance
• faint
• blackout
• swim

Adjective

• beautiful
• gorgeous
• lovely
• attractive
• cute
• handsome
• pretty
• stunning
• charming
• good

Verb

• wear
• kill
• exhaust
• tire
• drain
• wear out
• burn out

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

Noun

This Club World Cup has meant many things to many people, but all four Brazilian clubs making it to the knockout stage of the tournament — two of them featuring in the last eight — has represented something more fundamental. —Jordan Campbell, New York Times, 8 July 2025

Palmeiras, another profitable Brazilian club, also managed to make the CWC knockout stage. —Dan Bernstein, Sportico.com, 8 July 2025

Adjective

Since the tournament became a solely knockout competition in 2018, home teams have won exactly 54% of matches over 90 minutes. —Ian Nicholas Quillen, Forbes.com, 31 May 2025

Arteta understandably is more risk-averse in knockout European ties, but Premier League matches sometimes need to be forcibly opened up — even at the risk of fatigue or becoming defensively compromised. —Liam Tharme, New York Times, 13 Apr. 2025

Verb

Two years earlier, at the World Cup in France, they had also been knocked out at the first hurdle after three successive draws. —Jacob Whitehead, New York Times, 10 July 2025

This heady one-two punch of opium and alcohol was widely used to knock out pain or discomfort, whatever the cause. —Sam Kelly, Time, 8 July 2025

Word History

First Known Use

Noun

1887, in the meaning defined at sense 1a

Adjective

1818, in the meaning defined at sense 1

Verb

1856, in the meaning defined at sense 1

Phrases Containing knockout

• knockout drops
• technical knockout

Rhymes for knockout

• about
• bailout
• blackout
• blowout
• breakout
• burnout
• buyout
• checkout
• closeout
• cutout
• devout
• dropout

Kids 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 verb

ˈnäk-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