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.
1 eruption, eczema, redness, efflorescence, dermatitis:
One of the symptoms of measles is a skin rash.
2 number(s), quantity, lot(s), multitude, profusion, outbreak, series, succession, spate, wave, flood, deluge, plague, epidemic:
There's been a rash of burglaries in the neighbourhood.