representative vs proponent

representative and proponent both are nouns.

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

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

Other hypernyms of representative include advocate, advocator, exponent.

representative (noun)	proponent (noun)
an item of information that is typical of a class or group	a person who pleads for a cause or propounds an idea
a person who represents others
a member of the United States House of Representatives
an advocate who represents someone else's policy or purpose

representative (adjective)	proponent (adjective)
standing for something else
being or characteristic of government by representation in which citizens exercise power through elected officers and representatives
serving to represent or typify