Which of the following terms refers to initiating a legal action based on a falsehood?

The term that accurately describes initiating a legal action based on a falsehood is fraud. Fraud involves making deceptive statements or misrepresentations with the intent to gain something of value, such as initiating a legal action. In the context of legal actions, fraud refers specifically to the manipulation or misrepresentation of facts that leads another party to act in a way that causes them harm or loss.

Perjury pertains to lying under oath, generally in a judicial setting. While it reflects dishonesty, it does not encompass the broader concept of initiating false legal actions as fraud does. Deception is a more general term that refers to misleading someone but does not specifically relate to the context of legal action. False pretenses is often associated with obtaining property or money through deceit but does not solely emphasize the initiation of legal actions.

Thus, fraud is the most precise term when discussing the act of starting a legal process based on deceitful claims.