Definition of "impostor"

"It were dishonour in me to yield. I will not play the part of an impostor, whom my uncle must despise even while he screens. No; these estates are his right: let him take them; I will not buy them with his daughter's hand."

1837, L[etitia] E[lizabeth] L[andon], “The Consent”, in Ethel Churchill: Or, The Two Brides. […], volume I, London: Henry Colburn, […], page 153

“I said he had a criminal face.” “He can't help his face.” “He can help being a crook and an impostor. Calls himself a butler, does he? The police could shake that story. He's no more a butler than I am.”

1960, P[elham] G[renville] Wodehouse, chapter XX, in Jeeves in the Offing, London: Herbert Jenkins

Interestingly, Wang shows that Chinese allows the appearance of an indexical pronoun alongside the imposter, as in (31).

2014, Daniel Kaufman, “The Syntax of Indonesian Imposters”, in Chris Collins, editor, Cross-Linguistic Studies of Imposters and Pronominal Agreement, page 105

One possibility is that mothers of HR [higher-risk] infants frequently use non-pronoun forms in place of pronouns, as in the impostor uses noted above.

2018, Angela Xiaoxue He, Rhiannon Luyster, Sudha Arunachalam, “Personal pronoun usage in maternal input to infants at high vs. low risk for autism spectrum disorder”, in First Language, volume 38, number 5