# knockout

/ˈnɑˌkaʊt/ (US) · /nˈɒkaʊt/ (UK)

Source: https://englishreference.com/word/knockout
Updated: 2026-06-20

## Senses

### 1. combat sports

noun · CEFR B1

a hit that makes a fighter unconscious or unable to continue the fight.

For teachers: the act of rendering an opponent unconscious or unable to resume a contest within a specified time limit.

- The champion won the match with a powerful knockout in the third round.
- The referee stopped the bout immediately after the knockout, ensuring the medical team could attend to the fallen fighter without delay.

### 2. elimination tournament

noun · CEFR B2

a competition where a player or team is removed after losing one game.

For teachers: a tournament format in which the loser of each match is immediately eliminated from the competition.

- Our local team was eliminated in the first round of the knockout.
- The knockout stages of the tournament often produce more dramatic results because there is no margin for error in a single-elimination format.

### 3. attractive person

noun · CEFR B2 · Informal

someone who is extremely attractive or beautiful.

For teachers: an exceptionally attractive or impressive person, often used to describe a woman.

- Everyone turned to look when she walked in; she was a total knockout.
- The lead actress was a complete knockout, though critics argued that her performance lacked the depth required for such a complex role.

### 4. genetics

noun · CEFR C2 · Technical

the process of turning off a specific gene in a living thing for science.

For teachers: the genetic engineering technique of deactivating a specific gene to observe the resulting phenotypic changes.

- The scientists used a gene knockout to study how the heart develops.
- By creating a knockout mouse, the researchers were able to demonstrate that the specific protein was essential for long-term memory formation.

### 5. impressive or beautiful

adjective · CEFR B2 · Informal

extremely impressive, beautiful, or successful.

For teachers: strikingly attractive or impressive; having a powerful effect.

- She wore a knockout dress to the awards ceremony.
- The marketing team delivered a knockout presentation that secured the contract despite stiff competition from larger agencies.

## Examples

- The champion won the fight with a powerful knockout in the third round.
- She looked like a total knockout in her new evening gown at the gala.
- The tournament follows a knockout format, meaning any team that loses a single match is immediately eliminated from the competition.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.