pro-lifer vs exponent

pro-lifer and exponent both are nouns.

Word	Noun	Adjective	Verb	Adverb
pro-lifer	Yes	No	No	No
exponent	Yes	No	No	No

As nouns, exponent is a hypernym of pro-lifer; that is, exponent is a word with a broader meaning than pro-lifer:

pro-lifer: an advocate of full legal protection for embryos and fetuses; someone opposed to legalized induced abortion
exponent: a person who pleads for a cause or propounds an idea

Other hypernyms of pro-lifer include advocate, advocator, proponent.

pro-lifer (noun)	exponent (noun)
an advocate of full legal protection for embryos and fetuses; someone opposed to legalized induced abortion	a mathematical notation indicating the number of times a quantity is multiplied by itself
	a person who pleads for a cause or propounds an idea
	someone who expounds and interprets or explains