# impostor

/ˌɪmˈpɔstɝ/ (US) · /ɪmpˈɒstɐ/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/impostor
Updated: 2026-05-25

## Definition

someone who pretends to be a different person or to have a different identity. You use this when someone lies about who they are to trick others.

For teachers: a person who assumes a false identity or pretends to be someone else. Often used in the context of social engineering or psychological conditions where the individual believes they are not who they are.

## Examples

- The police arrested the impostor who tried to enter the building.
- The impostor used a stolen passport to board the flight and was only caught after the pilot noticed the mismatched photo.
- In the classic psychological study, the subject began to believe he was an impostor, convinced that his entire life was a series of borrowed identities rather than a genuine existence.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.