In religion and mythology, occultism and folklore, a demon (or daemon, daimon; from Greek δαίμων daimōn) is supernatural being that is generally described as a malevolent spirit.

In Ancient Near Eastern religions as well as in the derived Abrahamic traditions, including ancient and medieval Christian demonology, a demon is considered an “unclean spirit” which may cause demonic possession, to be addressed with an act of exorcism. Western occultism and Renaissance magic, which grew out of an amalgamation of pagan Greco-Roman, Jewish and Christian tradition, a demon is considered a spiritual entity that may be conjured and controlled.