ἄτρεστος
From LSJ
τῶν δ᾽ ὀρθουμένων σῴζει τὰ πολλὰ σώμαθ᾽ ἡ πειθαρχία → But of those who make it through, following orders is what saves most of their lives (Sophocles, Antigone 675f.)
English (LSJ)
ον, (τρέω)
A not trembling, fearless, Trag., and Pl.Cra.395c: c. gen., ἄ. μάχας fearless of fight, A.Pr.416 (lyr.); ἄ. ἐν μάχαις S.Aj. 365 (lyr.); ἄ. εὕδειν securely, Id.OT586. Adv. -τως A.Supp.240: neut. pl. ἄτρεστα as Adv., E.Ion1198.
German (Pape)
[Seite 388] nicht zitternd, unerschrocken, bes. Tragg., καρδία Aesch. Ag. 1375; μάχης Prom. 414; ἐν μάχαις Soph. Ai. 358; σὺν φόβοις entggstzt O. R. 586; ἄτρεστα adverbial Eur. Ion. 1198; so sp. D.; auch Plat. Crat. 395 b.