poor vs inadequate

poor is a noun but inadequate is not a noun.

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

As adjectives, poor and inadequate are synonyms defined as:

Other synonyms of poor include jejune, short.

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

poor (adjective)	inadequate (adjective)
having little money or few possessions	lacking the requisite qualities or resources to meet a task
lacking in quality or substances	of insufficient quantity to meet a need
characterized by or indicating poverty
of insufficient quantity to meet a need
deserving or inciting pity