From Longman Dictionary of Contemporary Englishstoolpigeonstool‧pi‧geon /ˈstuːlˌpɪdʒɪn/ noun [countable] American English informal SCCTELLsomeone, especially a criminal, who helps the police to catch another criminal, usually by giving them information SYN informerOrigin stoolpigeon (1800-1900) stoolpigeon “pigeon tied to a wooden frame to attract other birds for shooting at” ((1800-1900))
