Definition of Exceptio peremptoria
A peremptory exception; called also "perpetua," (perpetual); one which forever destroyed the subject - matter or ground of the action (qua semper rem de qua agitur perimit); such as the exceptio doli mail, the exception metus, etc.
That's the definition of Exceptio peremptoria in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.