hot on (something)
With a fervent enthusiasm for something. My daughter is now hot on baseball, so we're going to a game at the end of the month. Now that Cecil is hot on cooking, our kitchen is in a constant state of disarray.
hot on something
Fig. enthusiastic about something; very much interested in something; knowledgeable about something. Meg's hot on animal rights. Jean is hot on modern ballet just now.
1. Also, hot for. Enthusiastic about, as in She's really hot on golf, or He's hot for another skiing vacation. This seemingly modern slangy usage was first recorded in 1667. Also see make it hot for.
2. Also, hot at. Very good, impressive, as in He's hot at anything involving numbers. This expression, first recorded in 1573, is frequently used in the negative, as in I'm not so hot at new computer programs.