Emily Dickinson Lexicon

IM-POS'TOR, n. [Fr. imposteur; Sp. and Port. impostor; It. impostore; from Low L. impostor, from impono. See Impose.]

One who imposes on others; a person who assumes a character for the purpose of deception; a deceiver under a false character. It seems to be yet unsettled, whether Perkin Warbeck was an impostor. A religious impostor may be one who assumes the character of a preacher, without authority; or one who falsely pretends to an extraordinary commission from heaven, and terrifies people with denunciations of judgments. Encyc.