Green’s Dictionary of Slang

a member of the Irish nationalist movement Sinn Fein.

1921		King's Royal Rifle Corps Chron. 48: A strafe was carried out on Sinn Feiners piqueting Protestant shop. Since the arrival of troops [...] the ‘Shinners’ [...] appointed men to loiter through the streets.
1923		G.A. Birmingham Found Money 113: Sinn Fein, a name at which the world grows pale! And these profane Tommies turn it into ‘Shinners’.
1954–56		B. Behan ‘The Same Again, Please’ in After the Wake (1981) 111: It ’ung over the canteen counter – Beware – in black and red wool, till the Shinners let off a landmine.
1987		(con. 1920s) L. Redmond Emerald Square 7: He was a member of the guerilla force that broke the power of the British in the twenty-six counties, a ‘Shinner’.
1997		Irish Times 22 Feb. n.p.: He called Catholics ‘Shinners’ [BS].
2024		G. MacDonough X 11 June 🌐 Shinners do badly in Irish local elections.