Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
perpessĭo, ōnis, f. [perpetior], a bearing, suffering, enduring: harum rerum perpessio, Cic. Rab. Perd. 5, 16: laborum, id. Inv. 2, 54, 163: rerum arduarum ac difficilium, id. ib.: dolorum, id. Fin. 1, 15, 49: fortitudinis patientia et perpessio et tolerantia rami sunt, Sen. Ep. 67, 10: malae valetudinis et dolorum gravissimorum, id. ib. 66, 47.