unconventional
adjective/ˌʌnkənˈvɛnʃənl/ 
(often approving)not following what is done or considered normal or acceptable by most people; different and interesting
synonym unorthodoxan unconventional approach to the problemunconventional viewsThe magazine describes him as having unconventional good looks. antonym conventional unconventionality/ˌʌnkənˌvɛnʃəˈnælət̮i/
noun [uncountable] unconventionally/ˌʌnkənˈvɛnʃənəli/
adverbHe dresses unconventionally.