knuckle under: meaning, definition, pronunciation and examples

C1/C2
UK/ˌnʌk.əl ˈʌn.dər/US/ˌnʌk.əl ˈʌn.dɚ/

Informal/Idiomatic

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Quick answer

What does “knuckle under” mean?

To submit to authority, pressure, or force.

Audio

Pronunciation

Definition

Meaning and Definition

To submit to authority, pressure, or force; to give in or yield.

To accept defeat in an argument or conflict; to capitulate after resistance.

Dialectal Variation

British vs American Usage

Differences

The phrase is used and understood in both varieties. No significant structural differences.

Connotations

In both, it can imply weakness or pragmatic surrender. Perhaps slightly more common in American narrative contexts (e.g., describing someone refusing to 'knuckle under' to bullies).

Frequency

Low-to-medium frequency in both; not a daily expression but recognized by educated speakers.

Grammar

How to Use “knuckle under” in a Sentence

[Subject] knuckle under (to [Authority/Pressure/Person])

Vocabulary

Collocations

strong
refuse to knuckle underfinally knuckled underforced to knuckle under
medium
knuckle under to pressureknuckle under to demandsknuckle under to authority
weak
knuckle under completelyeventually knuckle undersimply knuckle under

Examples

Examples of “knuckle under” in a Sentence

verb

British English

  • The protestors held out for days but eventually knuckled under to the government's threats.
  • He's too stubborn to knuckle under, even when he's clearly wrong.

American English

  • The team refused to knuckle under to their rivals' aggressive tactics.
  • After the court order, the company finally knuckled under and paid the fine.

adverb

British English

  • No adverbial form in common use.

American English

  • No adverbial form in common use.

adjective

British English

  • No adjectival form in common use.

American English

  • No adjectival form in common use.

Usage

Meaning in Context

Business

Rare. Could describe a company yielding to regulatory pressure or a competitor.

Academic

Very rare. More likely in historical/political analysis describing groups submitting to power.

Everyday

Used in personal conflicts, parenting (children refusing to knuckle under to rules), or workplace dynamics.

Technical

Not used.

Vocabulary

Synonyms of “knuckle under”

Vocabulary

Antonyms of “knuckle under”

Watch out

Common Mistakes When Using “knuckle under”

  • Incorrect preposition: 'knuckle under for' (correct: 'knuckle under to').
  • Using it as a transitive verb: 'He knuckled under them.' (correct: 'He knuckled under to them.')

FAQ

Frequently Asked Questions

It is informal and idiomatic. Avoid it in very formal writing.

'Knuckle under' means to submit or yield. 'Knuckle down' means to start working hard on something.

Rarely. It usually implies a negative, reluctant submission. A positive submission (like agreeing wisely) would use 'yield' or 'concede'.

No. It is intransitive. The source of pressure is introduced with 'to' (e.g., 'knuckle under to pressure').

To submit to authority, pressure, or force.

Knuckle under: in British English it is pronounced /ˌnʌk.əl ˈʌn.dər/, and in American English it is pronounced /ˌnʌk.əl ˈʌn.dɚ/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • toe the line
  • give up the fight
  • throw in the towel

Learning

Memory Aids

Mnemonic

Imagine making a fist (with your knuckles) to fight, then turning your hand over (under) in a gesture of surrender.

Conceptual Metaphor

SUBMISSION IS PHYSICAL LOWERING/BOWING (knuckling under implies lowering oneself).

Practice

Quiz

Fill in the gap
After a week of parental pressure, the teenager finally and cleaned his room.
Multiple Choice

What is the closest meaning of 'knuckle under' in the sentence: 'The rebels refused to knuckle under, even when facing certain defeat.'?