elan vs eagerness

elan and eagerness both are nouns.

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

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

Other hypernyms of elan include avidity, avidness, keenness.

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