1. A confirmation of the validity or correctness of something previously established: "His re-election was a reaffirmation of his leadership skills."
2. Legally: An agreement that a debtor and a creditor enter into after a debtor has filed for bankruptcy, in which the debtor agrees to repay all or part of an existing debt after the bankruptcy case is over.

For instance, a debtor might make a reaffirmation agreement with the holder of a car note that the debtor can keep the car and must continue to pay the debt after bankruptcy.