willingness vs zeal

willingness and zeal both are nouns.

Word	Noun	Adjective	Verb	Adverb
willingness	Yes	No	No	No
zeal	Yes	No	No	No

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

Other hyponyms of willingness include eagerness, forwardness, readiness, openness, receptiveness, receptivity, wholeheartedness.

willingness (noun)	zeal (noun)
cheerful compliance	prompt willingness
	a feeling of strong eagerness (usually in favor of a person or cause)
	excessive fervor to do something or accomplish some end