messenger (n.)youdaoicibaDictYouDict[messenger 词源字典]
c. 1200, messager, from Old French messagier "messenger, envoy, ambassador," from message (see message (n.)). With parasitic -n- inserted by c. 1300 for no apparent reason except that people liked to say it that way (compare passenger, harbinger, scavenger).[messenger etymology, messenger origin, 英语词源]