postulate vs postulator

postulate and postulator both are nouns.

Word	Noun	Adjective	Verb	Adverb
postulate	Yes	No	Yes	No
postulator	Yes	No	No	No

postulate (noun)	postulator (noun)
(logic) a proposition that is accepted as true in order to provide a basis for logical reasoning	someone who assumes or takes something for granted as the basis of an argument
	(Roman Catholic Church) someone who proposes or pleads for a candidate for beatification or canonization

postulate (verb)	postulator (verb)
take as a given; assume as a postulate or axiom
maintain or assert
require as useful, just, or proper