From Longman Dictionary of Contemporary Englishbe hot on somethingbe hot on somethinginformal a) KNOW somethingto know a lot about something He’s pretty hot on aircraft. b) STRICT British English to be very strict about something SYN tight The company is very hot on security. → hot
Examples from the Corpus
be hot on something• Once again Biddy / Beth flees, but both the Toddler and McGarr are hot on her trail.• The flies buzz and the sun is hot on my spine.• Young Laura is hot on the heels of her brothers.• It was hot on the top and cold in the middle.• But they were hot on the trail of a loathsome whine as the party in another mess pined for better days. 