Gnostic

GNOSTICS. Early heretics who boasted of their superior knowledge, for that is the meaning of the word, just as agnostic  means without knowledge. This heresy dates back to Apostolic days, Simon Magus being considered its founder.

They mixed up the Christian faith with systems based on Platonism, Oriental Philosophy, or corrupt Judaism. St. John is believed to have written against the gnostics in certain parts of his Gospel.