a stool pigeon

stool pigeon

An informant, especially a criminal working as a spy for law enforcement officers. Although the criminal agreed to help the police in order to avoid prison time, he was afraid the other gang members would kill him if they discovered he was a stool pigeon.
See also: pigeon, stool

a stool pigeon

OLD-FASHIONED
A stool pigeon is someone who gives secret information to the police. There's nothing the mob hates more than a stool pigeon. Note: This expression is used to express disapproval. Note: This expression comes from the old practice of putting a wooden pigeon on a seat to trick other pigeons.
See also: pigeon, stool
References in periodicals archive ?
She could be an asset to Mano (elder brother) Digong because she would act as a stool pigeon.
He's also a drugs baron and when she interrupts him in the process of rubbing out a stool pigeon, she has to run for her life.
Police believe the pigeon was meant to represent a stool pigeon - a term for a grass or snitch.
She told us she couldn't possibly say because she didn't want to be labelled a stool pigeon.
Another television teenager, Meadow Soprano, was lucky: Her dad dropped her off at Bates, Bowdoin, and Colby because he had to track down and murder a stool pigeon.
A contrasting love stow develops between Boss Whalen's new secretary, Eva (Sherri Parker Lee), and his in-house spy, Canary Jim (Finbar Lynch), who's despised as a stool pigeon by his fellow inmates but who uses his compromised position to break the prison scandal to the world.