grass up
phrasal verbPart ofgrass
grass up — phrasal verb
1. to report someone's criminal activity to the police, often used in informal Brit
1.phrasal verb
Definition
to report someone's criminal activity to the police, often used in informal British English.
Example
Nobody in the neighbourhood would grass him up even though everyone knew what he had done.
Leo was afraid that his former partner would grass him up to avoid going to prison alone.