insufficient vs quantity

insufficient is not a noun while quantity is a noun.

Word	Noun	Adjective	Verb	Adverb
insufficient	No	Yes	No	No
quantity	Yes	No	No	No

insufficient (noun)	quantity (noun)
	how much there is or how many there are of something that you can quantify
	an adequate or large amount
	the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable

insufficient (adjective)	quantity (adjective)
of a quantity not able to fulfill a need or requirement