I have been both an Impersonator (one who pretends to be someone he's not) and an Impostor (who pretends to be something he's not). As to the latter, in undercover situations I have used my own name while pretending to be, for example, a dishonest warehouseman and a disabled person seeking a supernatural cure—see, respectively, "Thief" and Faith-Healing Subject. In the latter role, see "'John of God': Healings by Entities?" (Skeptical Inquirer 31:5, Sept./Oct. 2007, 20-22).