informer

Synonyms:

betrayer, blabber, rat, squealer

Types:

canary, fink, sneak, sneaker, snitch, snitcher, stool pigeon, stoolie, stoolpigeon

someone acting as an informer or decoy for the police

copper's nark, nark

an informer or spy working for the police

grass, supergrass

a police informer who implicates many people

Type of:

informant, source

a person who supplies information