Английский Этимологический словарь - wise (adj.)

- O.E. wis, from P.Gmc. *wisaz, from pp. adj. *wittos of PIE base *woid-/*weid-/*wid- "to see," hence "to know." Slang meaning "aware, cunning" first attested 1896. Related to the source of O.E. witan "to know, wit." Wiseacre (1595) is a 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 depricatory sense may have come through confusion with obsolete Eng. segger "sayer," which also had a sense of "braggart" (c.1440). Wise guy is attested from 1896; wisecrack is from 1924. Wisenheimer, with mock Ger. or Yiddish surname suffix, first recorded 1904.