sufficiency vs sufficient

sufficiency is a noun but sufficient is not a noun.

Word	Noun	Adjective	Verb	Adverb
sufficiency	Yes	No	No	No
sufficient	No	Yes	No	No

sufficiency (noun)	sufficient (noun)
the quality of being sufficient for the end in view
an adequate quantity; a quantity that is large enough to achieve a purpose
sufficient resources to provide comfort and meet obligations

sufficiency (adjective)	sufficient (adjective)
	of a quantity that can fulfill a need or requirement but without being abundant