a destroyer of sacred beliefs, systems or institutions;
e.g. She was an iconoclast, and was therefore never invited to anything with any religious undertones.
(noun)
a person who destroys images of religious figures because they believe that people are worshiping an image instead of the religious entity itself, which is a form of blasphemy;
e.g. The iconoclast was shunned from his heavily religious family after he destroyed the statues in their prayer room.