separatist
noun
a person who separates, withdraws, or secedes, as from an established church.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
In some countries a hyperchurchly trend of the national or state church is responsible for dissenting movements which, left to themselves, finally take the form of separatistic churches.
From The Lutherans of New York Their Story and Their Problems by George Wenner