Fraudulent means dishonest and deceptive, done with the intention to trick someone for personal gain. When something is fraudulent, it's deliberately fake or misleading, designed to make people believe something false so the deceiver can benefit.

A fraudulent scheme might promise people easy money if they send in cash, but the whole operation is a lie meant to steal their money. A fraudulent signature on a check means someone forged another person's name to steal funds. Scientists who publish fraudulent research deliberately fake their data or results, betraying the trust of everyone who relies on accurate information.

The word implies more than simple dishonesty: it suggests calculated deception. If you accidentally give wrong information, that's a mistake. But if you knowingly create fake documents or tell elaborate lies to trick someone out of money or property, that's fraudulent behavior.

Fraudulent actions are usually illegal because they involve deliberate deception for gain. Someone caught making fraudulent insurance claims by pretending to be injured when they're not can face serious legal consequences.