impostor Look up impostor at Dictionary.com
1586, from M.Fr. imposteur, from L.L. impostorem (nom. impostor), agent noun from impostus, collateral form of impositus, pp. of imponere "place upon, impose upon, deceive," from in- "in" + ponere "to put place" (see position). Imposture "act of willfully deceiving others" first recorded 1537.