millionaire vs wealthy person

millionaire and wealthy person both are nouns.

Word	Noun	Adjective	Verb	Adverb
millionaire	Yes	No	No	No
wealthy person	Yes	No	No	No

As nouns, wealthy person is a hypernym of millionaire; that is, wealthy person is a word with a broader meaning than millionaire:

millionaire: a person whose material wealth is valued at more than a million dollars
wealthy person: a person who possesses great material wealth

Other hypernyms of millionaire include adult male, man, have, rich person.

millionaire (noun)	wealthy person (noun)
a person whose material wealth is valued at more than a million dollars	a person who possesses great material wealth