Examples:

• Maybe you'll find your stool pigeon in tonight's shake up.
• You can't call him a stool pigeon, he considers himself a newspaperman.
• But where did they get this story about making me a stool pigeon?
• Get out of here, you stool pigeon.
• As a matter of fact, however... You look a bit like a stool pigeon.
• We're going to set up the stool pigeon, and then we wait.
• Chuck knew he would be in danger if the criminals found out he was a stool pigeon.
• Yes, initially, because he didn't want to be seen as a stool pigeon.