reckless

Synonyms: adventuresome adventurous any which way audacious brash breakneck carefree careless daredevil daring desperate devil-may-care fast and loose feckless foolhardy harebrained hasty headlong heedless helter-skelter hopeless hotheaded ill-advised imprudent inattentive incautious inconsiderate indiscreet kooky madcap mindless negligent overventuresome playing with fire precipitate rash regardless temerarious thoughtless uncareful venturesome venturous wild

Antonyms: careful cautious responsible wary