Rash

1. Acting too quickly without considering the consequences and risks; not careful; hasty. Synonyms: foolhardy, heady, impulsive, precipitate; reckless Antonyms: prudent, unrash, shy, timid, cautious, careful
2. (Northern England, archaic) Of corn or other grains: so dry as to fall out of the ear with handling.
3. (obsolete, rare)
   1. Requiring swift action; pressing; urgent.
   2. Taking effect quickly and strongly; fast-acting.