indispensableness vs indispensable

indispensableness is a noun but indispensable is not a noun.

Word	Noun	Adjective	Verb	Adverb
indispensableness	Yes	No	No	No
indispensable	No	Yes	No	No

indispensableness (noun)	indispensable (noun)
the quality possessed by something that you cannot possibly do without

indispensableness (adjective)	indispensable (adjective)
	not to be dispensed with; essential
	absolutely necessary; vitally necessary
	unavoidable