knave (n.)youdaoicibaDictYouDict[knave 词源字典]
Old English cnafa "boy, male servant," common Germanic (cognates: Old High German knabo "boy, youth, servant," German knabe "boy, lad," also probably related to Old English cnapa "boy, youth, servant," Old Norse knapi "servant boy," Dutch knaap "a youth, servant," Middle High German knappe "a young squire," German Knappe "squire, shield-bearer"). The original meaning might have been "stick, piece of wood" [Klein]. Sense of "rogue, rascal" first recorded c. 1200. In playing cards, "the jack," 1560s.[knave etymology, knave origin, 英语词源]