A more thorough explanation:

Definition: Nil debet is a Latin term that means "he owes nothing." It was used historically as a general denial in a debt action on a simple contract. In legal terms, it is a formal denial of the debt. It denies not only the existence of any contract, but under it any matters in excuse or in discharge may also be shown.

• John was sued for a debt he did not owe. He filed a plea of nil debet, denying the existence of any contract and stating that he owed nothing.
• In a debt action, the defendant can plead nil debet to deny the debt and any matters in excuse or discharge.

These examples illustrate how nil debet was used historically in legal proceedings to deny the existence of a debt and any related matters. It was a formal way for defendants to defend themselves against false accusations of owing money.