Opposite of mild-mannered

Hi

Harsh, cruel and unkind are a few antonyms of mild-mannered or gentle, I found in my dictionaries. I am not terribly happy with cruel or unkind. Some people are harsh without being cruel or unkind. It's just their tone or way of dealing with others.

Could you please offer me a word or expression that is used by native speakers for someone who is anything but mild-mannered or gentle?

Thanks,

Tom