iconoclast

iconoclast \ahy-KON-uh-klast\, noun:
a person who attacks cherished beliefs or institutions as foolish or wrong
In the end, Miles characterizes Zappa, for better or worse, as "an iconoclast in the male tradition of Neal Cassady, Hunter S. Thompson, William S. Burroughs, Ken Kesey, Allen Ginsberg, Lenny Bruce and the early Norman Mailer."
-- Carmela Ciuraru, LA Times, 2004-11-15
Al-Mutawa's decision to attend Tufts was also somewhat random - he followed the footsteps of a cousin - and, once there, he resumed his status as an iconoclast.
-- Jake Halpern, Boston Globe, 2007-10-14
by 1596, from French iconoclaste, from Middle Latin iconoclastes, from Late Greek eikonoklastes, from eikon "image" + klastes "breaker," from klan "to break." Originally the word referred those in the Eastern Church in 8th and 9th centuries whose mobs of followers destroyed icons and other religious objects on the grounds that they were idols. Extended sense of "one who attacks orthodox beliefs or institutions" is first attested 1842.