Green’s Dictionary of Slang

1. (US) fine, excellent, outstanding.

1903		Omaha Dly Bee (NE) 1 Mar. 23/4: There goes the stud bug of arithmetic!
1943		W. Guthrie Bound for Glory (1969) 135: Big Jim was the stud buzzard in our town that day.
1972		D. Jenkins Semi-Tough 283: It’s almost spring in New York, which I think is a pretty stud time of year.
1993		Eble Campus Sl. Oct. 5: stud – admirable, stylish: ‘That new shirt of yours is stud’.

2. (also studdish) aggressive.

1950		A.B. Guthrie Way West 55: Give some men a rifle and a piece of power [...] and they got too studdish to put up with.
1959		H. Ellison ‘No Game for Children’ in Gentleman Junkie (1961) 78: This wasn’t some stud punkie from uptown.

3. of homosexuals or lesbians, overtly masculine.

1971		R.D. Pharr S.R.O. (1998) 367: ‘Didn’t your husband knife you because you wouldn’t stay away from that stud bitch’.
1972		Sat. Rev. (US) 12 Feb. 24: Today’s homosexuals can be open (‘come out’) or covert (‘closet’), practicing or uninhibited [...] manly (‘stud’) or womanly (‘fem’).