A more thorough explanation:

Definition: Expressio falsi is a Latin term that refers to a false statement. If a false statement is made during a contract negotiation, it may result in the contract being rescinded or cancelled. This is because the false statement may have influenced one or both parties to agree to the terms of the contract.

Example: For example, if a car salesman tells a customer that a used car has never been in an accident when it actually has, this would be an expressio falsi. If the customer later finds out about the accident and can prove that the salesman made a false statement, they may be able to cancel the contract and return the car.

Another example: If a seller of a house tells a buyer that the roof is in good condition when it actually needs to be replaced, this would also be an expressio falsi. If the buyer later discovers the truth and can prove that the seller made a false statement, they may be able to rescind the contract and get their money back.

These examples illustrate how a false statement can have serious consequences in a contract negotiation. It is important for both parties to be truthful and transparent in their dealings to avoid any misunderstandings or legal issues.