Green’s Dictionary of Slang

1. a woman; also attrib.

c.1900		‘Ramrod’ Nocturnal Meeting 58: His usual term of endearment for me is ‘fat-arse or split-arse little fucker’.
1993		B. Moore Lex. of Cadet Lang. 364: usage: ‘Can’t make it. I’ve got to go out with my split arse tonight.’.
1996		Ottowa Citizen 19 May 4/5: ‘We were taught to refer to women as split arses and gutter sluts’.
1997		Guardian 24 June 4/5: She stood up for other wrens when subjected to unwanted attentions. Mrs O. and Miss Morris were both [...] called ‘splitarse’.
2003		Brummagem Dict. 🌐 : split-arse n. a derogatory term for a woman.
2019		Observer 14 Apr. 🌐 They called her names like ‘split arse’, blanked her or talked about her behind her back [...] ‘I would have people regularly say, “No offence to you, I just don’t agree with it [female firefighters]”.’.

2. (US) a male homosexual.

2001

OnLine Dict. of Playground Sl. 🌐 split arse n. homosexual male.