Lewis & Short

purgātōrĭus, a, um, adj. [purgo], cleansing, purgative, purgatory (post-class.): medicamentum, Symm. Ep. 6, 65.
Trop.: virtutes, Macr. Somn. Scip. 1, 8: poenae, Aug. Civ. Dei, 7, 7: tormenta, id. ib. 21, 16.