rich people vs people

rich people and people both are nouns.

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

As nouns, people is a hypernym of rich people; that is, people is a word with a broader meaning than rich people:

rich people: people who have possessions and wealth (considered as a group)
people: (plural) any group of human beings (men or women or children) collectively

rich people (noun)	people (noun)
people who have possessions and wealth (considered as a group)	(plural) any group of human beings (men or women or children) collectively
	the body of citizens of a state or country
	members of a family line
	the common people generally

rich people (verb)	people (verb)
	fill with people
	furnish with people