1. a person who is mentally ill or behaves in a wild, irrational way
Usage: can be considered offensive when referring to mental illness
2. a person who acts recklessly or with extreme enthusiasm
Usage: informal

Examples

• The driver sped through traffic like a madman.
• He worked on his invention like a madman, barely sleeping for days.
• The crowd cheered as the madman attempted the dangerous stunt.
• She called him a madman for quitting his job without another one lined up.
• The madman’s reckless behavior endangered everyone around him.
• He danced like a madman at the concert.