c. 1200, a shortening of Old French escarn "mockery, derision, contempt," a common Romanic word (Spanish escarnio, Italian scherno) of Germanic origin, from Proto-Germanic *skarnjan "mock, deride" (source also of Old High German skern "mockery, jest, sport," Middle High German scherzen "to jump with joy").
Probably influenced by Old French escorne "affront, disgrace," which is a back-formation from escorner, literally "to break off (someone's) horns," from Vulgar Latin *excornare (source of Italian scornare "treat with contempt"), from Latin ex- "without" (see ex-) + cornu "horn" (see horn (n.)).
c. 1200, from Anglo-French, Old North French escarnir (Old French escharnir), from the source of scorn (n.). Cognate with Old High German skernon, Middle Dutch schernen. Related: Scorned; scorning. Forms in Romanic languages influenced by confusion with Old French escorner "deprive of horns," hence "deprive of honor or ornament, disgrace."