insufficient vs poor

insufficient is not a noun while poor is a noun.

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

insufficient (noun)	poor (noun)
	people without possessions or wealth (considered as a group)

insufficient (adjective)	poor (adjective)
of a quantity not able to fulfill a need or requirement	having little money or few possessions
	lacking in quality or substances
	characterized by or indicating poverty
	of insufficient quantity to meet a need
	deserving or inciting pity