1. adjective /kiːn/
a) showing a quick and ardent willingness or responsiveness, enthusiastic, eager; interested, intense.
"Of full keen will." -Piers Plowman.
"So keen and greedy to confound a man." -Shak.
Syn: prompt, eager, ardent, sharp, acute, cutting, penetrating, biting, severe, sarcastic, satirical, piercing, shrewd
2. verb /kiːn/
a) To sharpen; to make cold.
"Cold winter keens the brightening flood." -Thomson.
b) To utter a keen.
Keen—meaning brisk? Nay, here the Language warps:Tis singing bawdy Ballads to a Corpse.
See Also: keener
3. noun /kiːn/
A prolonged wail for a deceased person.
Wikipedia foundation.