enthusiast
Pronunciation: /ɪnˈθjuːzɪast, ɛn-/
noun

Origin:
early 17th century (denoting a person believing that he or she is divinely inspired): from French enthousiaste or ecclesiastical Latin enthusiastes 'member of a heretical sect', from Greek enthousiastēs 'person inspired by a god', from the adjective enthous (see enthusiasm)