If someone is 'a hot head', they are very likely to get angry easily. You might imagine their head heating up and exploding with anger! Likewise, if you're 'hot-headed' or 'a hot-headed person', you are prone to losing your temper or acting without thinking things through. You might hear this in any context, social or professional.

1. James can be a bit of a hot head, so people tend to be careful about what they say to him.
2. If someone becomes hot-headed when you give them feedback, it is a good indication that they do not respond well to criticism.

1. There's no room for hotheadedness in a classroom. As a teacher, you should be rational and controlled at all times.
2. Alex scuppered the deal by losing his temper during the negotiations. Someone so hot-headed should not have been part of the negotiating team.