Green’s Dictionary of Slang

(Aus.) a nickname for anyone called Oscar.

1914		Sport (Adelaide) 7 Aug. 5/3: Ocar D. [...] had a dark half-gour in the supper room. Was the coffee strong, Ock?
1916		R.H. Adams diary 26 Feb.n.p.: Considerable helio work done on the station owing to fault on line to Bde. called up by Ocker’s Co. Heard a voice, could swear it was Jim’s [AND].
1927		Sun. Sun (Sydney) 1 May (Sunbeams Supplement) 1: You know what I did to ‘Ocker’ Stevens at school on Wednesday don’t you? [AND].
1935		K. Tennant Tiburon 42: Okker Slade’s bag shelter had joined those of Dutch and Old Grey in the little circle round the fire.
1943		Bulletin (Sydney) 20 Oct. 13/1: ‘Ocker’ Simpson quoted the legendary ‘Crooked’ Mick of Speewah Bluff shed and the duffs he cooked for the shearers.
1959		J. Cleary Strike me Lucky 39: Then Ocker Oodskirt gave voice [...] Ocker is the porter at the railway station.
1972		Bulletin (Sydney) 26 Feb. 11/1: I only realised afterwards that I was suspected of being ‘Ocker’ Campbell, the notorious Australian smash and-grab man.