impostor
im-POS-ternounMeaning a person who pretends to be someone else to fool others
Memory hook im-POSE-ter: he POSES as another. Rex puts on a chef’s hat and a fake mustache and poses as the famous Chef Sven, until the real Sven walks in; Rex is an impostor.
The man at the door claimed to be from the water company, but he was an impostor with a fake badge.
In context Everyone believed the stranger was the old captain’s long-lost nephew until a neighbor who knew the family arrived and exposed him as an impostor.
Similar fraud, fake, phony, pretender
From Late Latin impostor, “a deceiver,” from imponere, “to put upon, to impose on (someone).”