Green’s Dictionary of Slang

1. as pfx, male.

1838		‘Paul Pry’ Oddities of London Life II 233: ‘How long is it, my good sir, [...] since you turned bull-nurse?’ The defendant said that he carried about the ‘chilthar’ to give them a little fresh air, and that his wife was too ill to attend to them.
1838		‘Paul Pry’ Oddities of London Life II 233: ‘I wouldn’t acared about it if he didn't bull-nurse at the same time: he used for to carry that ere baby in one hand, while he swept up the mud’.

2. (US) large, powerful, authoritative.

1840		T. Haliburton Clockmaker III 45: If there was a thing on airth that Ahab hated like pison, I do believe it was a great bull-nigger.
1845		R.S. Surtees Hillingdon Hall I 48: The great Bull niggers, that he had never seen or cared to set eyes upon.
1850		(con. 1843) Melville White-Jacket (1990) 279: May-Day was a full-blooded bull-negro—so the sailors called him—with a skull like an iron tea-kettle.
1850		Manchester Spy (NH) 21 Sept. n.p.: [of a turtle] ‘The bull bed-bug, sure, that has been atein’ the children for the past two months’.
1895		S.F. Chron. 6 June 11/5: Youse see a banker — de old man — stakes me wid a flat joint one day [...] Dead easy graft, but he sends a bull con along to guard his dough.
1927		H.F. Barker ‘More Hobo Lingo’ in AS II:12 506: ‘Bull’ as an adjective commonly means ‘large’.
1935		(con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 579: ‘Pipe down!’ a bull voice called out.
1944		O. Ferguson ‘Vocab. for Lakes [etc.]’ AS XIX:2 104: The hard work on [a ship] is muling or bull-work.
1957		D. Alexander ‘Bad Word’ in Best of Manhunt (2019) [ebook] He was trying to handle a big bull rattler [...] and it sank its fangs right into his bare arm.
1960		(con. 1950-1960) R.A. Freeman Dict. Inmate Sl. (Walla Walla, WA) 19: Bull-cook – a flunkey who does the heavy and dirty work for the chef.

3. (US gay) of a lesbian or male homosexual, masculine, aggressive.

1963		J. Rechy City of Night 232: Lesbians — femme and bull types.
1972		B. Rodgers Queens’ Vernacular 38: bull (’40s) [...] 3. (adj) masculine ‘Is he bull or cow when it comes to the sack?’.
1998		R. Scott Rebecca’s Dict. of Queer Sl. 🌐 bull — [...] 2) (adj) butch.
2004		Guardian Rev. 5 Mar. 9/3: Genuine prison life is more cliche-ridden. Fixers and barons, kind screws and brutes, bull queers, dodgy governors.