Impostor (noun)

1. A person who deceives others by pretending to be someone else.
2. A person who claims to have qualifications, credentials or experiences that they do not have.

Origin:

The word 'impostor' is derived from the latin word 'impostor' which means 'deceiver'. it has been in use in english since the early 17th century.

Examples:

1. The impostor claimed to be a doctor and managed to fool the hospital staff for several months.
2. The police finally caught the impostor who had been posing as a famous actor.
3. The impostor's scheme was uncovered when a victim of his fraud alerted the authorities.
4. The CEO was shocked to learn that the impostor who had stolen company secrets was a former employee.
5. The impostor's convincing performance convinced many people to invest their money in his fraudulent scheme.