secularist vs proponent

secularist and proponent both are nouns.

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

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

secularist: an advocate of secularism; someone who believes that religion should be excluded from government and education
proponent: a person who pleads for a cause or propounds an idea

Other hypernyms of secularist include advocate, advocator, exponent.

secularist (noun)	proponent (noun)
an advocate of secularism; someone who believes that religion should be excluded from government and education	a person who pleads for a cause or propounds an idea