Where does “occultism” come from?

Occultism derives from English occult, Ancient Greek -ισμός, Ancient Greek -μός, Latin ob-, Proto-Indo-European ḱēl-, Proto-Indo-European ḱel-, Ancient Greek ὀβελός, and Ancient Greek βέλος meaning to conceal or hide.

occultism (English): The study of the supernatural; A belief in occult...