poor vs poor people

poor and poor people both are nouns.

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

As nouns, poor and poor people are synonyms defined as:

poor and poor people: people without possessions or wealth (considered as a group)

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

poor (adjective)	poor people (adjective)
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