A more thorough explanation:

Acquietandis plegiis is a legal term that means "for acquitting sureties". It refers to a writ that was used in the past to force a creditor to release a surety from their obligation when the debt had been paid off.

For example, let's say that John borrowed $10,000 from a bank and his friend Tom acted as a surety for the loan. If John fails to repay the loan, the bank can demand payment from Tom. However, if John repays the loan in full, Tom can use the writ of acquietandis plegiis to force the bank to release him from his obligation as a surety.

Another example would be if a landlord required a tenant to have a co-signer on their lease agreement. If the tenant pays their rent on time and in full, the co-signer can use the writ of acquietandis plegiis to be released from their obligation as a surety.

These examples illustrate how the writ of acquietandis plegiis was used to protect sureties from being held responsible for a debt that had already been paid off or fulfilled.