elan vs avidity

elan and avidity both are nouns.

Word	Noun	Adjective	Verb	Adverb
elan	Yes	No	No	No
avidity	Yes	No	No	No

As nouns, avidity is a hypernym of elan; that is, avidity is a word with a broader meaning than elan:

Other hypernyms of elan include avidness, eagerness, keenness.

elan (noun)	avidity (noun)
enthusiastic and assured vigor and liveliness	a positive feeling of wanting to push ahead with something
distinctive and stylish elegance
a feeling of strong eagerness (usually in favor of a person or cause)