1. hot (to the touch)
顔が燃えているように熱い。My face is hot as if it is burning.
2. passionate (feelings, etc.); ardent; hot (e.g. gaze)
3. hot (e.g. temper)
4. zealous; enthusiastic; fired up
みんな熱くなってしまっている。Everyone has gotten fired up.
5. intense; severe; extreme
6. hot (topic); of interest