sharpness or cutting ability / astuteness or sagacity / eagerness or enthusiasm

plural of keenness

(chiefly Commonwealth of Nations) Often with a prepositional phrase, or with to and an infinitive: showing a quick and ardent responsiveness or willingness; eager, enthusiastic, interested.

(transitive, rare) To make cold, to sharpen.

A prolonged wail for a deceased person.

(intransitive) To utter a keen. / (transitive) To utter with a loud wailing voice or wordless cry. / (transitive) To mourn.

Sharp, shrill, especially of a sound.

Intense mournful wailing after a death, often at a funeral or wake / (by extension) An unpleasant wailing sound.

present participle of keen

(UK, parts of North America) fond of; appreciative of