He is a 'madman' out on the ski slopes. [=he is an extremely daring or reckless skier]
He drives 'like a madman'. [=he drives very recklessly]
a celebrity being stalked by a 'madman'
(..) Good. You're in the great game now. And the great game's terrifying. The only people who aren't afraid of failure are madmen like your father. Do you know what frightens me? I said farewell to a man who loves me. A man I thought I cared for. And I felt nothing. Just impatient to get on with it. (..)2016 TvShow: Game of Thrones Title: The Winds of Winter Season: 6 Episode 10