stool pigeon
[noun]
Synonyms: informer, betrayer, canary, fink, nark, snitch, squealer, stoolie, tattler, tipster

[TahlilGaran] English Synonym Dictionary ▲

stool pigeon
a person, especially a criminal, who secretly gives information to the police in order to help them catch other criminals

[TahlilGaran] Dictionary of Contemporary English ▲

stool pigeon
a person, especially a criminal, who secretly gives information to the police in order to help them catch other criminals.
Once they discovered he was a stool pigeon, it was only a matter of time before they had him killed.

[TahlilGaran] English Idioms Dictionary ▲

stool pigeon
n. A criminal who informs on his associates.
The detective was able to solve the crime mainly through information obtained from a stool pigeon.

[TahlilGaran] English Idioms Dictionary ▲