A hothead is someone who’s suddenly and easily angered or agitated. It’s usually a hothead who starts a riot or turns a peaceful protest violent.
A friend who seems calm one minute and furious the next is a hothead — and if you’ve ever witnessed a “road rage” incident involving an unreasonably angry driver, you know how unpredictable a hothead can be. This useful noun has been around since the 17th century, influenced by the Old English equivalent, hatheort or “hot heart,” and Elizabethan English’s hot-brain.
a reckless impetuous irresponsible person
a belligerent grouch