RASH

adj. impetuous, impulsive, unthinking, thoughtless, foolhardy, unconsidered, ill-considered, ill-advised, injudicious, imprudent, indiscreet, precipitate, hasty, careless, heedless, reckless, headlong, wild, madcap, hare-brained, hotheaded, adventurous, quixotic, venturesome, audacious, bold, dashing, brash, devil-may-care It was rash of him to try to sail round the world single-handed, but he did it