• (n.) One aiming at or pretending to a greater purity of like than others about him; -- applied to persons of various sects. See Albigenses.
Cath'a·rist noun [ Late Latin catharista , from Greek ... clean, pure.] One aiming at or pretending to a greater purity of like than others about him; -- applied to persons of various sects. See Albigenses . 
Catharist From Ecclesastical history, a member of any of various sects aiming at purity.