Source : Webster's Revised Unabridged Dictionary (1913)

Religionist \Re*li"gion*ist\, n.
   One earnestly devoted or attached to a religion; a religious
   zealot.

         The chief actors on one side were, and were to be, the
         Puritan religionists.                    --Palfrey.

         It might be that an Antinomian, a Quaker, or other
         heterodo? religionists, was to be scourged out of the
         town.                                    --Hawthorne.

Source : WordNet®

religionist
     n : a person who manifests devotion to a deity [syn: {religious
         person}] [ant: {nonreligious person}]