exorcism
n. the act or practice in which supposed evil spirits are expelled from a person believed to be possessed, or a place thought to be haunted, by means of certain rites, ceremonies, prayers, and incantations. It was once widely believed that such spirits were the major cause of mental disease and other disorders and that exorcism was therefore a suitable form of treatment. The Roman Catholic Church still performs ritual exorcisms in certain very restricted circumstances. See also inhabitance. —exorcise
vb.
—exorcist
n.