sufficiency vs suffice

sufficiency is a noun but suffice is not a noun.

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

sufficiency (noun)	suffice (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 (verb)	suffice (verb)
	be sufficient; be adequate, either in quality or quantity