- (superl.) Acute of mind; sharp; penetrating; having or expressing mental acuteness; as, a man of keen understanding; a keen look; keen features.
- (superl.) Bitter; piercing; acrimonious; cutting; stinging; severe; as, keen satire or sarcasm.
- (v.i.) To wail as a keener does.
- (superl.) Piercing; penetrating; cutting; sharp; -- applied to cold, wind, etc,; as, a keen wind; the cold is very keen.
- (n.) A prolonged wail for a deceased person. Cf. Coranach.
- (v.t.) To sharpen; to make cold.
- (superl.) Eager; vehement; fierce; as, a keen appetite.
- (superl.) Sharp; having a fine edge or point; as, a keen razor or a razor with a keen edge.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). keen. Retrieved September 24, 2026, from http://smartdefine.org/keen/definitions/2025189 |
| Chicago | Webster's. 2011. "keen" http://smartdefine.org/keen/definitions/2025189 (accessed September 24, 2026). |
| Harvard | Webster's 2011, keen, Smart Define, viewed 24 September, 2026, <http://smartdefine.org/keen/definitions/2025189>. |
| MLA | Webster's. "keen" 27 May 2011. Web. 24 September 2026. <http://smartdefine.org/keen/definitions/2025189> |