So what exactly is a lien?
A lien is a legal “encumbrance” registered on a person’s property to secure a debt the property owner owes to another person/business (commonly a bank/lender). In the case of a car loan, a bank (or finance company) will register a lien against the vehicle giving them the right to take possession of it should the borrower default on the loan and to sell the vehicle to recoup the outstanding debt.
So it’s really important you DON’T buy a vehicle with an outstanding lien!