keen

a. [ Compar. Keener superl. Keenest. ] [ OE. kene sharp, bold, AS. cēne bold; akin to D. koen, OHG. kuoni, G. kühn, OSw. kyn, kön, Icel. kænn, for kœnn wise; perh. akin to E. ken, can to be able. √45. ] 1. Sharp; having a fine edge or point; as, a keen razor, or a razor with a keen edge. [ 1913 Webster ]

A bow he bare and arwes [ arrows ] bright and kene. Chaucer. [ 1913 Webster ]

That my keen knife see not the wound it makes. Shak. [ 1913 Webster ]

2. Acute of mind; sharp; penetrating; having or expressing mental acuteness; as, a man of keen understanding; a keen look; keen features. [ 1913 Webster ]

To make our wits more keen. Shak. [ 1913 Webster ]

Before the keen inquiry of her thought. Cowper. [ 1913 Webster ]

3. Bitter; piercing; acrimonious; cutting; stinging; severe; as, keen satire or sarcasm. [ 1913 Webster ]

Good father cardinal, cry thou amen
To my keen curses. Shak. [ 1913 Webster ]

4. Piercing; penetrating; cutting; sharp; -- applied to cold, wind, etc.; as, a keen wind; the cold is very keen. [ 1913 Webster ]

Breasts the keen air, and carols as he goes. Goldsmith. [ 1913 Webster ]

5. Eager; vehement; fierce; as, a keen appetite. “Of full kene will.” Piers Plowman. [ 1913 Webster ]

So keen and greedy to confound a man. Shak. [ 1913 Webster ]

6. Wonderful; delightful; marvelous; as, that would be keen. [ slang ] [ PJC ]

☞ Keen is often used in the composition of words, most of which are of obvious signification; as, keen-edged, keen-eyed, keen-sighted, keen-witted, etc.

Syn. -- Prompt; eager; ardent; sharp; acute; cutting; penetrating; biting; severe; sarcastic; satirical; piercing; shrewd. [ 1913 Webster ]