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n. One who postulates.

n. Roman Catholic Church A church official who presents a plea for canonization or beatification.

n. A person who postulates something as the basis of an argument

n. A Roman Catholic official who makes the case for the beatification of a proposed saint

n. someone who assumes or takes something for granted as the basis of an argument

n. (Roman Catholic Church) someone who proposes or pleads for a candidate for beatification or canonization

"The Vatican named Father Mode as "postulator," or promoter of the cause, and a tribunal was established to interview witnesses to Father Capodanno's life."

declarer    asserter    asseverator    affirmer    avower