heretic
noun
her·e·tic
| \ ˈher-ə-ˌtik
, ˈhe-rə-\
, ˈhe-rə-\
Definition of heretic
1
religion
: a person who differs in opinion from established religious dogma (see dogma sense 2)
especially
: a baptized member of the Roman Catholic Church who refuses to acknowledge or accept a revealed truth
The church regards them as heretics.
2
: one who differs in opinion from an accepted belief or doctrine : nonconformist