Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
perpes, ĕtis, adj. [like perpetuus, from per-peto], lasting throughout, continuous, uninterrupted, continual, perpetual (anteand post-class.): perpetem pro perpetuo dixerunt poëtae, Fest. p. 217 Müll.: luna proprio suo perpeti candore, App. de Deo Socr. init.: silentium, id. Flor. 3, p. 357, 27: rivus cruore fluebat perpeti, Prud. Cath. 10, 42.
- B. Esp., of time, continuous, never ending, perpetual, entire, whole: noctem perpetem, Plaut. Am. 1, 1, 125; 2, 2, 100; id. Truc. 2, 2, 23: nocte perpeti, Just. 5, 7, 6; Capitol. Ver. 4: perpetem diem alternis pedibus insistunt, Sol. 52: per annum perpetem, Lact. Mort. Pers. 33 fin.: perpes aevi aeternitas, Jul. Val. Rer. Gest. Alex. M. 1, 34 Mai.
Hence, adv.: perpĕtim, constantly, without intermission, perpetually, App. Mag. p. 321, 5 (but in Plin. 20, 6, 21, § 44, the correct read. is perpetuo; v. Sillig ad h. l., and Hand, Turs. 4, p. 465).