informer
/ɪnˈfɔːmə
/noun
A person who informs on another person to the police or other authority.The prosecutors knew the case details as provided by the undercover police officers, the informers and the supervisors....
- Police informers are often identified by number rather than by name, for obvious security reasons.
- The other travelers seemed embarrassed but passive, perhaps the legacy of years of informers and secret police.
Synonyms
informant;
betrayer, traitor, Judas, collaborator, double-crosser, fifth columnist, double agent, spy, infiltrator, plant, turncoat;
North American tattletale
informal rat, squealer, stool pigeon, stoolie, telltale, tale teller, whistle-blower, snake in the grass, canary, snitch, peacher
British informal grass, supergrass, nark, snout, nose
Scottish informal clype
Scottish & Northern Irish informal tout
North American informal fink
Australian/New Zealand informal fizgig, pimp, shelf
archaic intelligencer, beagle