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what is a grass in british slang

In British slang, a “grass” is someone who informs on others to the police or authorities – basically, a snitch or informer. It can also be used as a verb (“to grass someone up”), meaning to tell the police or a person in power what they did.

What Is a “Grass” in British Slang?

In UK slang, grass most commonly means:

  • A police informer or snitch – someone who tells the authorities about other people’s crimes.
  • By extension, anyone who betrays someone’s trust by revealing secrets, especially to people in authority (teachers, bosses, etc.).

You’ll also see it used in phrases like:

  • “He’s a grass.” = He’s a snitch.
  • “Who grassed me up?” = Who told on me to the police/teacher/boss?
  • “Don’t grass on your mates.” = Don’t inform on your friends.

Where the Slang Comes From (Quick Story Style)

The slang use of “grass” dates back to around the 1920s–30s in Britain. Etymologists point to two main ideas:

  1. Cockney rhyming slang
    • “Grasshopper” rhymes with “copper” (an old slang term for a police officer).
    • Over time, “grasshopper” was shortened to “grass,” and the meaning shifted from “police” to “police informer.”
  1. “Snake in the grass” association
    • The older phrase “snake in the grass” means a hidden, treacherous person.
    • Some writers suggest “grass” took on that sense of hidden betrayal, fitting how informers operate.

Either way, by mid‑20th century Britain, “grass” was established as standard criminal and street slang for an informer, with related forms like “grasser” and later “supergrass” (a big informer who gives evidence on many people at once).

Other Meanings of “Grass” (Context Matters)

“Grass” is very context-dependent, so in British English it can mean several things:

[3] [8][3] [9][3] [2][3] [6][9]
Meaning Context Example
Ordinary grass (plants) Everyday literal English “Keep off the grass.”
Marijuana/cannabis General English slang “They were smoking some grass.”
Informer / snitch British slang (crime, street, youth culture) “He’s a grass – don’t trust him.”
To grass (up/on) British phrasal verb “Someone grassed him up to the police.”
Supergrass British legal/crime slang “The supergrass testified against the whole gang.”
So if you see a British forum post saying:

“Don’t be a grass.”

they are not talking about lawns or weed – they mean “don’t snitch.”

Mini Forum‑Style Takes

You’ll often see different attitudes to “grass” in online discussions:

  1. Street/loyalty angle
    • “Being a grass is the worst thing you can be, you don’t rat on your mates.”
    • Here, loyalty to friends or crew is treated as more important than cooperating with authorities.
  2. Legal/moral angle
    • “If someone’s dangerous, grassing them up is the right thing to do.”
    • From this view, “grass” is just a loaded word for something that can be socially responsible.
  3. Casual/school angle
    • Teens might use “grass” about telling a teacher: “He grassed to Miss about the fight.”
    • It doesn’t have to be serious crime – any “telling on” can count in slang.

These competing views are why the word carries a heavy social charge; being labelled a “grass” is usually negative in British culture.

Quick Usage Guide

If you’re learning British English:

  1. Use “grass” (noun) carefully.
    • It’s quite strong – like calling someone a snitch – and is usually insulting.
  1. “Grass up/on” as a verb is informal.
    • Fine in casual speech, TV, movies, or dialogue, but not in formal writing.
  1. Let context guide you.
    • If the sentence involves crime, the police, school rules, or “getting in trouble,” “grass” probably means informer.
    • If it’s about smoking or drugs, it likely means marijuana.

SEO Bits: Focus on “what is a grass in british slang”

  • Primary sense : police informer / snitch in UK slang.
  • Related phrases : “grass up,” “grass on,” “supergrass,” “grasser.”
  • Trending context : Still widely used in British TV, crime dramas, and online forum discussion about loyalty vs. justice, especially in UK‑based shows and youth culture.

Meta description suggestion:
“Wondering what ‘grass’ means in British slang? Learn how it’s used for informers, where it comes from, and how phrases like ‘grass up’ work in real UK conversations.” TL;DR: In British slang, a “grass” is a police informer or snitch, and to “grass someone up” means to tell the authorities or a person in power what they did.

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