Green’s Dictionary of Slang

1. one who is particularly proficient at an occupation or activity, esp. a successful gambler.

1899		W.J. Kountz Billy Baxter’s Letters 34: A Messe de Mariage seems to be some kind of a wedding march, and a bishop who is a real hot dog won’t issue a certificate unless the band plays the Messe.
1902		Ade Breaking Into Society (1904) 184: I sometimes suspect that I am not qualified to be a Hot Dog.
a.1948		(con. early 1930s) C. McKay Harlem Glory (1990) 52: Stop kidding, sweet-back. [...] Can’t I see you’re on easy street, you hot dog.
1966		Atlantic Monthly Mar. 131: We had this one player [...] who could hit nine out of ten from the foul line with his back to the basket. He was a real hot dog.
1979		T. Alibrandi Killshot 49: They’re hot dogs. They beat out-of-shape business men all year for a chance to play each other.
1987		C. Hiaasen Double Whammy (1990) 31: They [i.e. professional anglers] sound like hot dogs, Ott. I just want to relax.

2. a show-off.

1900		E.H. Babbitt ‘College Words and Phrases’ in DN II:i 42: hot-dog, n. A conceited person.
1960		J. Brosnan Long Season 221: ‘He may be a Hot Dog but I don’t know where Scheffing would be without him’.
1965		T. Wolfe Kandy-Kolored Tangerine-Flake Streamline Baby (1966) 97: They have to design a car they can sell to the farmer in Kansas as well as the hot dog in Hollywood.
1976		(con. 1969) C.R. Anderson Grunts 99: Can you believe it – some hot dog up on a pallet with his shirt off, actually trying to get a fucking suntan.
1981		J. Wambaugh Glitter Dome (1982) 134: A trio of black hot dogs in black-on-black with black boots.
1998		K. Anderson Night Dogs 22: [of police] They were the troublemakers, hot dogs, bad boys, adrenalin junkies back from Vietnam.
2001		J. Stahl Plainclothes Naked (2002) 250: Manny Rubert. That arrogant . . . hot dog!

3. in ironic use, an unpleasant or incompetent person.

1967–8		Baker et al. CUSS 139: Hot dog An obnoxious person.
1975		J. Wambaugh Choirboys (1976) 31: Like most hotdogs he wore his cap tipped forward until the brim almost touched his nose.

4. something exciting, amusing.

1967

M. Braly On the Yard (2002) 139: Whenever he started a new one [i.e. book] he’d say, ‘This is a real hotdog—’ and give an involved description of the plot.