late 14c., "exorcism," from Late Latin adiurationem (nominative adiuratio) "a swearing to," noun of action from past-participle stem of Latin adiurare "to put (someone) to an oath," from ad "to" (see ad-) + iurare "swear," from ius (genitive iuris) "law," from PIE root *yewes- "law" (see jurist). Originally a term in exorcism (with conjuration); the general sense "a solemn oath, a charging under the penalty of a curse" is from 17c.
