keen 1 (kēn)
adj. keen·er, keen·est
1. Having a fine, sharp cutting edge or point.
2. Having or marked by intellectual quickness and acuity. See Synonyms at sharp.
3. Acutely sensitive: a keen ear.
4. Sharp; vivid; strong: "His entire body hungered for keen sensation, something exciting" (Richard Wright).
5. Intense or bracing: a keen wind.
6. Pungent; acrid: A keen smell of skunk was left behind.
a. Ardent; enthusiastic: a keen chess player.
b. Eagerly desirous: keen on going to Europe in the spring.
8. Slang Great; splendid; fine: What a keen day!
[Middle English kene, from Old English cēne, brave.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.