anti-conventional
adjective
an·ti-con·ven·tion·al 
ˌan-tē-kən-ˈvench-nəl,
-ˈven(t)-shə-nᵊl,
ˌan-tī- : opposed to conventional methods and attitudes : emphatically and deliberately unconventional
running an anti-conventional campaign
Word History
First Known Use
1826, in the meaning defined above