enthusiasm vs eagerness

enthusiasm and eagerness both are nouns.

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

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

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

enthusiasm (noun)	eagerness (noun)
overflowing with eager enjoyment or approval	prompt willingness
a lively interest	a positive feeling of wanting to push ahead with something
a feeling of excitement