# belt up

CEFR B2 · Phrasal verb

Source: https://englishreference.com/word/belt-up
Updated: 2026-04-24

## Definition

to stop talking or to be quiet, often used when you are annoyed with someone.

For teachers: to cease speaking immediately; typically used as an imperative in a rude or informal register to silence another person.

## Examples

- Just belt up and let me finish my work.
- The teacher told the rowdy students to belt up so she could begin the lesson.
- He was about to reveal the secret when his sister told him to belt up before the neighbors overheard their conversation.

## Pitfalls

- Not "He belted up his mouth." but "He belted up." — this phrasal verb is usually intransitive when it means 'be quiet' and does not take an object like 'mouth'.

## Usage notes

- highly informal and can be perceived as rude or aggressive depending on the relationship.
- Teaching tip: note that in British English, this can also mean to fasten a seatbelt, though the 'be quiet' sense is a common idiomatic usage to teach alongside 'shut up'.

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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.