A reckless impetuous irresponsible person.

synonyms: harum-scarum, hothead, lunatic, madcap, swashbuckler.

Roget 863: rashness etc. adj.; temerity, want of caution, imprudence, indiscretion; overconfidence, presumption, audacity.    precipitancy, precipitation; impetuosity; levity; foolhardihood^†, foolhardiness; heedlessness, thoughtlessness etc. (inattention) 458; carelessness etc. (neglect) 460; desperation; Quixotism, knight-errantry; fire eating.    gaming, gambling; blind bargain, leap in the dark, leap of faith, fool's paradise; too many eggs in one basket.    desperado, rashling^†, madcap, daredevil, Hotspur, fire eater, bully, bravo, Hector, scapegrace, enfant perdu [Fr.]; Don Quixote, knight-errant, Icarus; adventurer; gambler, gamester; dynamitard^†; boomer [U.S.].    ... show more

Dutch: snoever, waaghals
Polish: artysta, egzemplarz, ptaszek, ziółko

Presumptuously daring:
— A daredevil test pilot having the right stuff.

synonym: temerarious.