enthusiasm vs avidness

enthusiasm and avidness both are nouns.

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

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

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

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