im·pos·tor or im·pos·ter (ĭm-pŏs'tər) n. One who engages in deception under an assumed name or identity.
[French imposteur, from Latin impostor, one who assigns a name, from impostus, variant of impositus, past participle of impōnere, to place upon; see impose.]
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.
Main Entry: im·pos·tor Variant: orim·pos·ter/im-'päs-t&r/ Function: noun : one that assumes a false identity or title for the purpose of deception :IMPERSONATOR