Iconoclast
/aɪˈkɑːnəˌklæst/ noun hardA person who challenges or attacks widely accepted beliefs, traditions, or institutions.
The young architect was an iconoclast, rejecting every convention of the style she had been trained in.
Memory Trick
Breaks into Greek roots for 'icon' (a sacred image) and 'clast' (to break, as in geology's 'clastic' rock) — an iconoclast literally smashes icons, and figuratively smashes cherished ideas.