Happy Ordinary Teacher. It usually refers to middle aged or older teachers who have hit a comfortable salary and just do minimal work. They usually reject all other extra workload.

HOT does not exist for the younger generation anymore. Increments, promotions and progressions have slowed down a lot. If they reject workload and want to be HOT, might as well just resign for better prospects outside. The younger ones can only be SOTs now. Either way also will be SOT.