G-mann.

1917 M. Skinnider Doing Bit for Ireland 177 One morning I was informed there was a ‘G-man’, as we call government detectives, waiting down-stairs to see me.

1922 J. Joyce Ulysses ii. viii. [Lestrygonians] 155 Jack Power could a tale unfold: father a G man.

1922 J. Joyce Ulysses ii. xii. [Cyclops] 287 The bloody old lunatic is gone round to Green Street to look for a G. man.

1926 P. Béaslaí Michael Collins I. v. 107 The political detectives of the ‘G’ division of the Dublin Police came like a flock of carrion crows to pick out ‘suspects’... Anyone who had seen that sight may be pardoned if he felt little compunction at the subsequent shooting of these same ‘G’ men.

1930 F. D. Pasley Al Capone (1931) i. 33 He offered a G man (Government agent) ten gran' to forget it.

1935 Punch 3 July 6/2 For G-men, as they are called.., form the new licensed killers organised by the Federal Government to override all State laws in the suppression of gangster crime and the capture of every Public Enemy.

1946 P. G. Wodehouse Joy in Morning iii. 24 He was still giving me that searching look, like a G-man hobnobbing with a suspect.

1958 Spectator 3 Oct. 447/1 Mr. Hoover has built up..an immense personal reputation..by creating a legend of the G-man that has largely transferred the romantic interest from the robbers to the cops.