madcap

Behaving or acting impulsively or rashly; wild.

A person who acts madly or wildly; a flighty or harebrained person; one who indulges in frolics.

Pertaining to or resembling a madcap; wild; harum-scarum.

A person of wild behavior; an excitable, rash, violent person.

Inclined to wild sports; delighting in rash, absurd, or dangerous amusements.