stealthiness vs secretiveness

stealthiness and secretiveness both are nouns.

Word	Noun	Adjective	Verb	Adverb
stealthiness	Yes	No	No	No
secretiveness	Yes	No	No	No

As nouns, secretiveness is a hypernym of stealthiness; that is, secretiveness is a word with a broader meaning than stealthiness:

stealthiness: a disposition to be sly and stealthy and to do things surreptitiously
secretiveness: characterized by a lack of openness (especially about one's actions or purposes)

Other hypernyms of stealthiness include closeness.

stealthiness (noun)	secretiveness (noun)
a disposition to be sly and stealthy and to do things surreptitiously	characterized by a lack of openness (especially about one's actions or purposes)
	the trait of keeping things secret