Two: Religionist (American).
The OED’s definition of this is, “One addicted to religion; one imbued with, or zealous for, religion. Sometimes in bad sense, a religious zealot or pretender”. The examples here given show that through the seventeenth centuries in England religionists were contrasted with atheists. Webster’s dictionary echoes the English definition and does not go beyond; yet lately in the United States religionists are referred to in the current press, it is clear that this term includes anyone who is professionally occupied with religion, of whatever church, movement or status – that is, anyone from Billy Graham to Reinhold Niebuhr.