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
British Dictionary definitions for wise-acre
a person who wishes to seem wise
a wise person: often used facetiously or contemptuously
[C16: from Middle Dutch wijsseggher soothsayer; related to Old High German wīssaga, German Weissager. See wise1, say]
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).