keenness vs keen

keenness and keen both are nouns.

Word	Noun	Adjective	Verb	Adverb
keenness	Yes	No	No	No
keen	Yes	Yes	Yes	No

keenness (noun)	keen (noun)
thinness of edge or fineness of point	a funeral lament sung with loud wailing
a quick and penetrating intelligence
a positive feeling of wanting to push ahead with something

keenness (adjective)	keen (adjective)
	excellent
	intense or sharp
	having or demonstrating ability to recognize or draw fine distinctions
	having a sharp cutting edge or point
	painful as if caused by a sharp instrument

keenness (verb)	keen (verb)
	express grief verbally