sharp; having a fine edge or point; as, a keen razor, or a razor with a keen edge.-acute of mind; sharp; penetrating; having or expressing mental acuteness; as, a man of keen understanding; a keen look; keen features.-bitter; piercing; acrimonious; cutting; stinging; severe; as, keen satire or sarcasm.-piercing; penetrating; cutting; sharp; -- applied to cold, wind, etc, ; as, a keen wind; the cold is very keen.-eager; vehement; fierce; as, a keen appetite.-to sharpen; to make cold.-a prolonged wail for a deceased person.  cf. coranach.-to wail as a keener does.