advocate, advocator, exponent, proponent - a person who pleads for a cause or propounds an idea

anglophil, anglophile - an admirer of England and things English

believer, truster - a supporter who accepts something as true

Boswell - a devoted admirer and recorder of another's words and deeds

cheerleader - an enthusiastic and vocal supporter; "he has become a cheerleader for therapeutic cloning"

Confederate - a supporter of the Confederate States of America

enthusiast, partizan, partisan - an ardent and enthusiastic supporter of some person or activity

Francophil, Francophile - an admirer of France and everything French

free trader - an advocate of unrestricted international trade

functionalist - an adherent of functionalism

Jacobite - a supporter of James II after he was overthrown or a supporter of the Stuarts

loyalist, stalwart - a person who is loyal to their allegiance (especially in times of revolt)

New Dealer - a supporter of the economic policies in the United States known as the New Deal

Graecophile, philhellene, philhellenist - an admirer of Greece and everything Greek

mainstay, pillar - a prominent supporter; "he is a pillar of the community"

Roundhead - a supporter of Parliament and Oliver Cromwell during the English Civil War

seconder - someone who endorses a motion or petition as a necessary preliminary to a discussion or vote

Shavian - an admirer of G. B. Shaw or his works

endorser, indorser, ratifier, subscriber - someone who expresses strong approval

well-wisher, sympathiser, sympathizer - someone who shares your feelings and expresses sympathy or hopes that something will be successful

toaster, wassailer - someone who proposes a toast; someone who drinks to the health of success of someone or some venture

maintainer, sustainer, upholder - someone who upholds or maintains; "firm upholders of tradition"; "they are sustainers of the idea of democracy"

verifier, voucher - someone who vouches for another or for the correctness of a statement

Whig - a supporter of the American Revolution

character, fictional character, fictitious character - an imaginary person represented in a work of fiction (play or film or story); "she is the main character in the novel"

antihero - a protagonist who lacks the characteristics that would make him a hero (or her a heroine)