The noun referring to one who takes an assumed identity in order to deceive is variously spelled imposter and impostor. Impostor has the edge, and it is the form recommended by most English reference sources, but imposter is not wrong. Not only is it nearly as common as impostor, but it is also nearly as old. Impostor came to English from the French imposteur in the late 16th century,1 and imposter first appeared almost immediately thereafter.2 And though the -or spelling has always been more common, imposter has always been present to some degree.