nonconformist

Short definition from Wiktionary

Noun

1. 1
   A member of a church separated from the Church of England; a Protestant dissenter.
2. 2
   Loosely, a Christian who does not conform to the doctrines of an established church.
3. 3
   Someone who does not conform to accepted beliefs, customs or practices.
4. 4
   A noctuid moth (Lithophane lamda).
5. 5
   A member of a Protestant church which does not observe the doctrines of the established church, especially of the Church of England.

Adjective

1. 1
   Not conforming to established customs, etc.