acute

acute \uh-KYOOT\, adjective:

1. acting keenly on the senses; sharp
2. quick in discernment; drawing fine distinctions
3. of an angle, less than 90 degrees
4. happening quickly, briefly, and severely

I find the pain of a little censure, even when it is unfounded, is more acute than the pleasure of much praise.
-- Thomas Jefferson

by 1570, from Latin acutus "sharp, pointed." Medical sense of "fever or disease that comes and goes quickly" (rather than a chronic one) first recorded 1667.