Esotericism

Esotericism or Esoterism signifies the holding of esoteric opinions or beliefs, that is, ideas preserved or understood by a small group or those specially initiated, or of rare or unusual interest. The term derives from the Greek ἐσωτερικός (esôterikos), a compound of ἔσω (esô): "within", thus "pertaining to the more inward", mystic. Its antonym is "exoteric".