Webster’s Revised Unabridged Dictionary · 1913
Exitial
Ex·i′tial, 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.