grass up: meaning, definition, pronunciation and examples
LowInformal, Colloquial
Quick answer
What does “grass up” mean?
To inform on or betray someone, especially to an authority figure, about their wrongdoing.
Audio
Pronunciation
Definition
Meaning and Definition
To inform on or betray someone, especially to an authority figure, about their wrongdoing.
A phrasal verb, chiefly British and Irish English, meaning to act as an informant, typically in a secretive or treacherous manner, causing trouble for the person being reported.
Dialectal Variation
British vs American Usage
Differences
Predominantly British and Irish. The equivalent American term is typically "rat out" or "snitch on." "Grass" as a noun for an informant is rare in American English.
Connotations
In UK usage, carries strong connotations of betrayal within a group (e.g., schoolchildren, colleagues, criminal underworld). Less common in formal or neutral contexts.
Frequency
Common in UK/Irish informal speech, especially among younger generations and in crime-related media. Very rare to non-existent in standard American English.
Grammar
How to Use “grass up” in a Sentence
[SUBJECT] grass [OBJECT] up (to [AUTHORITY])Vocabulary
Collocations
Examples
Examples of “grass up” in a Sentence
verb
British English
- If you grass me up to the teacher, I'll never speak to you again.
- He was grassed up by his own brother.
- Don't be a grass—nobody grasses up their mates.
American English
- He ratted out his friends to the principal. (US equivalent)
- She snitched on her coworkers. (US equivalent)
adverb
British English
- Not applicable for this phrasal verb.
American English
- Not applicable for this phrasal verb.
adjective
British English
- He's a grass. (noun used as modifier)
- A grass informant.
American English
- He's a snitch. (US equivalent)
Usage
Meaning in Context
Business
Extremely rare. Would imply severe breach of collegial trust, e.g., 'He grassed up his manager to HR about the fudged numbers.'
Academic
Not used.
Everyday
Used in informal settings: school, work, community, e.g., talking about someone telling a teacher or parent.
Technical
Not used. The legal term is 'act as an informant' or 'turn state's evidence.'
Watch out
Common Mistakes When Using “grass up”
- *He grassed the police up. (Incorrect order) -> He grassed him up to the police.
- *She grassed up about the plan. (Missing object) -> She grassed him up about the plan.
- Using it in formal writing.
FAQ
Frequently Asked Questions
It is strongly derogatory when applied to the informant, implying they are disloyal and untrustworthy. It is not a swear word, but a strong insult in certain contexts.
The noun is 'a grass' (informant). Example: 'He's a grass.' This is also informal and derogatory.
Yes, it can be used for any scenario where one person reports another's minor misbehaviour to an authority figure, like in a school or workplace.
'Grass up' is more specific to British English and often implies a more serious betrayal, potentially with legal consequences. 'Tell on' is more general, used especially by children, and is common in both UK and US English.
To inform on or betray someone, especially to an authority figure, about their wrongdoing.
Grass up is usually informal, colloquial in register.
Grass up: in British English it is pronounced /ɡrɑːs ʌp/, and in American English it is pronounced /ɡræs ʌp/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “No honour among thieves (related concept)”
- “to turn King's/Queen's evidence (formal/legal equivalent)”
Learning
Memory Aids
Mnemonic
Think of 'grass' as the green stuff you walk on. If you 'grass someone up,' you are putting them under your foot (betraying them) and leaving them 'flat' or in trouble.
Conceptual Metaphor
INFORMING IS REVEALING WHAT IS HIDDEN (like grass covering the ground). BETRAYAL IS STEPPING ON SOMEONE (to grass on someone).
Practice
Quiz
In which variety of English is 'grass up' most commonly used?