enthusiasm vs keenness

enthusiasm and keenness both are nouns.

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

As nouns, keenness is a hyponym of enthusiasm; that is, keenness is a word with a more specific, narrower meaning than enthusiasm:

Other hyponyms of enthusiasm include gusto, relish, zest, zestfulness, avidity, avidness, eagerness, exuberance, technophilia.

enthusiasm (noun)	keenness (noun)
overflowing with eager enjoyment or approval	thinness of edge or fineness of point
a lively interest	a quick and penetrating intelligence
a feeling of excitement	a positive feeling of wanting to push ahead with something