Occult means "hidden". It covers practices that are not approved of by God e.g., astrology (Isaiah 47:13), casting spells (Deut. 18:11), consulting with spirits (Deut. 18:11), magic (Gen. 41:8), sorcery (Exodus. 22:18), witchcraft (Deut. 18:10), and spiritism (Deut. 18:11). Those who practice the occult open themselves up to demonic activity, possession, and oppression.
Occult practices such as Ouija boards, tarot cards, Wicca, astrology charts, contacting the dead, séances, etc. are to be avoided by the Christian and Jews alike.