Grass someone up
Meaning
To inform authorities or someone in power about another person's wrongdoing, often betraying their trust.
Origin
The phrase "grass someone up" is widely believed to originate from Cockney rhyming slang. The term "grass" likely derived from "grasshopper," which cunningly rhymes with "copper," a long-standing slang term for a police officer. This linguistic trick emerged from the bustling streets of 20th-century London, serving as a covert way to speak about informing the police. As a result, to "grass someone up" quickly became a vivid and culturally embedded idiom, denoting the act of betrayal through informing, particularly within contexts where loyalty among peers was paramount.
Examples
- If you grass someone up to the police, you might be seen as a snitch by the others involved.
- The teacher asked who broke the window, but no one wanted to grass their friends up.