Green’s Dictionary of Slang

a boxer, a fighter (lit. or fig.).

1932		‘P.P.’ Rhy. Sl.
1960		J. Franklyn Dict. of Rhy. Sl. 133/2: Typewriter A fighter.
1972		Dodson & Saczek Dict. of Cockney Rhy. Sl.
1992		R. Puxley Cockney Rabbit.