# grass on

CEFR C1 · Phrasal verb

Source: https://englishreference.com/word/grass-on
Updated: 2026-04-24

## Definition

to tell the police or someone in charge about something bad that another person did.

For teachers: to inform an authority figure or the police about a person's illicit or prohibited activities; functions as a transitive verb of betrayal.

## Examples

- He refused to grass on his friends.
- The gang members were worried that one of their own might grass on them to the police.
- Despite the pressure from investigators, the witness remained silent, unwilling to grass on the individuals who had orchestrated the scheme.

## Pitfalls

- Not "He grassed his brother." but "He grassed on his brother." — the particle 'on' is required to indicate the person being reported.

## Usage notes

- usually followed by the person being reported; carries a strong negative connotation of being a 'snitch'.
- Teaching tip: this is a highly regional British term; compare it with the American 'snitch on' or 'rat out' to help students understand the cultural equivalent.

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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.