(n.) A clergyman or layman who promotes revivals of religion; an advocate for religious revivals; sometimes, specifically, a clergyman, without a particular charge, who goes about to promote revivals. Also used adjectively.

adorer beadsman celebrant chapelgoer churchgoer colporteur communicant congregation daily communicant evangelist idolater missionary missionary apostolic missionary rector missioner petitioner prayer suppliant supplicant supplicator venerator votary worshiper