Exitial \Ex*i"tial\, Exitious \Ex*i"tious\, a. [L. exitialis, exitious, fr. exitium a going out, a going to naught, i. e., ruin, fr.exire to go out: cf. F. exitial.] Destructive; fatal. [Obs.] "Exitial fevers." --Harvey. [1913 Webster]