G-man
slang An FBI agent. The "G" is thought to have originally been an abbreviation for "government." Come on, that guy definitely looks like a G-man, and if a G-man is tailing us, then they must know about our Ponzi scheme!
G-man
(ˈdʒimæn) n. a government investigative agent; an FBI agent. The G-men busted in and started shooting.