nullifier vs proponent

nullifier and proponent both are nouns.

Word	Noun	Adjective	Verb	Adverb
nullifier	Yes	No	No	No
proponent	Yes	No	No	No

As nouns, proponent is a hypernym of nullifier; that is, proponent is a word with a broader meaning than nullifier:

nullifier: an advocate of nullification; someone who believes that a state can resist federal laws
proponent: a person who pleads for a cause or propounds an idea

Other hypernyms of nullifier include advocate, advocator, exponent.

nullifier (noun)	proponent (noun)
an advocate of nullification; someone who believes that a state can resist federal laws	a person who pleads for a cause or propounds an idea
an official who can invalidate or nullify