madcap

Dictionary definition · madcap

noun

a reckless impetuous irresponsible person

adjective

characterized by undue haste and lack of thought or deliberation"a hotheaded decision"

Similar words

brainish hotheaded impetuous impulsive tearaway daredevil harum-scarum hothead lunatic swashbuckler

Source: Open English WordNet (CC BY 4.0).