A more thorough explanation:

Definition: Pact de non alienando is a Latin term used in civil law to refer to an agreement not to sell or transfer encumbered property, especially mortgaged property. This agreement allows the mortgagee to proceed directly against the mortgaged property without notice to the purchaser.

Example: If John takes out a mortgage on his house, he may agree to a pact de non alienando with the mortgage lender. This means that John cannot sell or transfer ownership of the house without the lender's permission. If John defaults on the mortgage, the lender can foreclose on the property without having to notify any subsequent purchasers.

Explanation: The example illustrates how a pact de non alienando works in practice. By agreeing not to sell or transfer the mortgaged property without the lender's permission, the borrower gives the lender greater security and control over the property. If the borrower defaults on the mortgage, the lender can foreclose on the property without having to go through the legal process of notifying any subsequent purchasers.