28 Moby Thesaurus words for "plainclothesman": Bow Street runner, FBI, FBI agent, Federal, G-man, Secret Service, Sherlock, Sherlock Holmes, T-man, detective, dick, fed, hawkshaw, hotel detective, house detective, house dick, inquiry agent, investigator, narc, operative, police detective, private detective, private investigator, revenuer, sleuth, store detective, tec, treasury agent