Madman (noun)

A man who is insane or mentally unwell.

Origin:

The word "madman" originated in the late 14th century from the old english word "gemædman", which means "mad or insane person".

Examples:

1. He was considered a madman by all who knew him.
2. The madman was ranting and raving on the street corner.
3. He was locked up in the asylum with other madmen.
4. The madman's wild eyes showed the depths of his madness.
5. The villagers were afraid of the madman, but he was really quite harmless.