WordNet (r) 3.0 (2006):

Catharism
    n 1: a Christian movement considered to be a medieval descendant
         of Manichaeism in southern France in the 12th and 13th
         centuries; characterized by dualism (asserted the
         coexistence of two mutually opposed principles, one good
         and one evil); was exterminated for heresy during the
         Inquisition [syn: Albigensianism, Catharism]