late 14c., from Old French profaner, prophaner (13c.) and directly from Latin profanare "to desecrate, render unholy, violate," from profanus "unholy, not consecrated" (see profane (adj.)). Related: Profaned; profaning.
mid-15c., "un-ecclesiastical, secular," from Old French profane (12c.) and directly from Latin profanus "unholy, not consecrated," according to Barnhart from pro fano "not admitted into the temple (with the initiates)," literally "out in front of the temple," from pro- "before" (see pro-) + fano, ablative of fanum "temple" (see feast (n.)). Sense of "unholy, polluted" is recorded from c.1500. Related: Profanely.