profanation n.

mid-15c., prophane, "un-ecclesiastical, secular, not devoted to sacred purposes, unhallowed," from Old French prophane, profane (12c.) and directly from Latin profanus (in Medieval Latin often prophanus) "unholy, not sacred, not consecrated;" of persons "not initiated" (whence, in Late Latin, "ignorant, unlearned"), also "wicked, impious."

According to Lewis & Short, de Vaan, etc., this is from the phrase pro fano, literally "out in front of the temple" (here perhaps with a sense of "not admitted into the temple (with the initiates)," from pro "before" (from PIE root *per- (1) "forward," hence "in front of, before") + fano, ablative of fanum "temple" (from PIE root *dhes-, forming words for religious concepts). The sense of "irreverent toward God or holy things" is from 1550s. Related: Profanely.