populist vs advocate

populist and advocate both are nouns.

Word	Noun	Adjective	Verb	Adverb
populist	Yes	No	No	No
advocate	Yes	No	Yes	No

As nouns, advocate is a hypernym of populist; that is, advocate is a word with a broader meaning than populist:

populist: someone who advocates the rights of the common people over those of the elite
advocate: a person who pleads for a cause or propounds an idea

Other hypernyms of populist include advocator, exponent, proponent.

populist (noun)	advocate (noun)
someone who advocates the rights of the common people over those of the elite	a person who pleads for a cause or propounds an idea
	a lawyer who pleads cases in court

populist (verb)	advocate (verb)
	push for something
	speak, plead, or argue in favor of