exorcise

(ĕk'sôr-sīz', -sər-)

1. To expel (an evil spirit) by or as if by incantation, command, or prayer.
2. To free from evil spirits or malign influences.

[Middle English exorcisen, from Late Latin exorcizāre, from Greek exorkizein : ex-, out of; see exo- + horkizein, to make one swear (from horkos, oath).]

WORD HISTORY   An oath is to be found at the etymological heart of exorcise, a term going back to the Greek word exorkizein, meaning "to swear in," "to take an oath by," "to conjure," and "to exorcise." Exorkizein in turn is formed from the prefix ex-, "thoroughly," and the verb horkizein, "to make one swear, administer an oath to," derived from horkos, "oath." Our word exorcise is first recorded in English in a work composed possibly before the beginning of the 15th century, and in this use exorcise means "to call up or conjure spirits" rather than "to drive out spirits," a sense first recorded in 1546.