Origin: late Middle English shamfron < Anglo-French, Old French champfrein, perhaps for *chafrein (with -m- perhaps from chamfreinchamfer, though the senses are unrelated), noun derivative of chafre(s)ner literally, to put a bridle on < Vulgar Latin *cap(um) head (for caput;see chief) + *-frenāre, verbal derivative of Latin frēnum bridle