repudiate

transitive verb | \ ri-ˈpyü-dē-ˌāt \ | re·pu·di·ate
  1. : to disavow or reject an obligation (as a debt) or duty (as performance under a contract); specifically : to indicate an inability or unwillingness to perform as promised under (a contract) : to indicate an inability or unwillingness to perform as promised under (a contract)