ἰΰ
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)
exclam. of surprise, Hdn.Gr.1.506.
Greek (Liddell-Scott)
ἰΰ: θαυμαστικὸν ἐπιφώνημα, Θεογνώστ. Κανόνες 161, Ἰω. Ἀλεξ. τονικὰ παραγγέλματα 37.