Imposture is the act of deceiving people by pretending to be someone you're not, or by claiming skills and knowledge you don't actually have. When someone commits imposture, they're creating an entire false identity or pretending to have credentials they never earned, going far beyond a small fib.

History is full of famous impostors. One man pretended to be a doctor for years, despite never attending medical school. Another impostor convinced people he was a prince and lived in luxury on others' generosity. In each case, the imposture eventually collapsed when the truth emerged.

Imposture differs from simply making a mistake about who you are. It requires deliberate deception and usually involves gaining something: money, respect, or opportunities. If you accidentally get credit for someone else's work, that's not imposture. But if you purposely take credit for their accomplishment and build a reputation on that lie, you're committing imposture.

While people sometimes use “imposter” as a simpler spelling, imposture specifically names the act of this deception, while impostor names the person doing it.