1585-95; < Middle Dutchwijssager prophet, translation of Middle High Germanwīssage,late Old High Germanwīssago, by popular etymology equivalent to wīs wise + sago sayer, from earlier wīzzago wise person; cognate with Old Englishwītega, akin to wit2
1595, partial translation of M.Du. wijssegger "soothsayer" (with no derogatory connotation), probably altered by association with M.Du. segger "sayer" from O.H.G. wizzago "prophet," from wizzan "to know," from P.Gmc. *wit "know." The depreciatory sense of "one who pretends to know everything" may have come through confusion with obsolete Eng. segger "sayer," which also had a sense of "braggart" (c.1440).