heresy Look up heresy at Dictionary.com
"an opinion of private men different from that of the catholick and orthodox church" [Johnson], early 13c., from O.Fr. heresie, from L. hæresis, "school of thought, philosophical sect," used by Christian writers for "unorthodox sect or doctrine," from Gk. hairesis "a taking or choosing," from haireisthai "take, seize," middle voice of hairein "to choose," of unknown origin. The Greek word was used in N.T. in ref. to the Sadducees, Pharisees, and even the Christians, as sects of Judaism, but in English bibles it is usually translated sect. Meaning "religious belief opposed to the orthodox doctrines of the Church" evolved in L.L. in the Dark Ages.