grass on
Advanced (C1) slang
To secretly tell the police or someone in charge about what another person has done wrong.
"Nobody likes him at school because he's always grassing on his classmates."
Hear it in context
A Dark Fantasy Audiobook: Reborn With A Divine System And Hidden Power (Book 1-4) | Complete Series
NoirCast · 2525:05
through the tall grass on the hilly open plains.
Dangerous Killer Bees, Spiky Plants, & Giant Centipedes | A Triple Threat for Coyote!
Brave Wilderness Top Videos · 73:21
They're walking around eating grass on horse stuff.
I Was An Undercover Cop — These Are The Cases That Almost Killed Me
Ian Bick · 48:08
and he's literally going from the grass on the right
I FOOLED Villagers With 1,000,000 HEARTS In Minecraft!
PrestonPlayz · 5:41
It's a slime block, but it's got grass on it.
100 Iconic Moments From Sir David Attenborough | BBC Earth
BBC Earth · 153:31
Forever chasing the seasonal growth of the grass on which they depend.