The word "fraud" is used for a person or an action that is not truthful, or it is fake. Fraud is also a term used when someone has committed a crime involving a form of illegal deception:
The young woman guilty of mail fraud went to jail for two years.
The credit card company sent us a fraud alert, warning us that someone was trying to use our credit card.
Accusations of fraud followed an investigation into a company’s claim that its products could cure cancer.
A judge can help determine if fraud did indeed take place.
Federal, state, and local governments have to deal with fraud and waste on a daily basis.
Once everyone realized the man was a fraud, he left his position in disgrace.
He’s a fraud and a con man.
The man’s a fraud.
The word "fraudulent" is an adjective:
Allegations of abuse turned out to be fraudulent.
Claims by the manufacturer that the pills would a make a person stronger turned out to be fraudulent.
Fraudulent email sent to thousands of people told them that they would inherit over a million dollars if they contacted the attorney managing the inheritance.
Beneath his clothing the man wore a gadget that made him look larger and stronger than he really was. What a fraud!