Green’s Dictionary of Slang

very skilful at.

1934		P. Allingham Cheapjack 70: They’re dead hot on the hustle [...] They’re hot on the moody, too.
1947		D. Davin For the Rest of Our Lives 309: Remember the pongos were never too hot on timing.
1953		‘John Eagle’ Hoodlums (2021) 76: Barney was hot on the kidding, a perpetual razzer.
1956		‘Charles Raven’ Und. Nights 33: He was very hot on the psychological side.
1970		H.E. Bates A Little of What You Fancy (1985) 535: She knew she wasn’t very hot on world affairs.
1980		M. Bail Homesickness (1999) 161: I’m not so hot on names.