ephemeralness vs transitoriness

ephemeralness and transitoriness both are nouns.

Word	Noun	Adjective	Verb	Adverb
ephemeralness	Yes	No	No	No
transitoriness	Yes	No	No	No

As nouns, transitoriness is a hypernym of ephemeralness; that is, transitoriness is a word with a broader meaning than ephemeralness:

ephemeralness: the property of lasting for a very short time
transitoriness: an impermanence that suggests the inevitability of ending or dying

Other hypernyms of ephemeralness include transience, transiency.

ephemeralness (noun)	transitoriness (noun)
the property of lasting for a very short time	an impermanence that suggests the inevitability of ending or dying