stool pigeon

Từ điển WordNet v3.1 - WordNet Dictionary

noun

1. someone acting as an informer or decoy for the police
• Syn:
fink, snitch, snitcher, stoolpigeon, stoolie,
sneak, sneaker, canary
• Derivationally related forms:
snitch (for: snitcher), snitch (for: snitch), fink (for: fink)
• Hypernyms:
informer, betrayer, rat, squealer, blabber
2. a dummy pigeon used to decoy others
• Hypernyms:
bait, decoy, lure