οὐά
From LSJ
ξένῳ δὲ σιγᾶν κρεῖττον ἢ κεκραγέναι → it's better for a stranger to keep silence than to shout (Menander)
English (LSJ)
or οὐᾶ, Lat.
A vah! exclam. of admiration, or of astonishment, Arr.Epict.3.22.34, D.C.63.20; of irony, Ev.Marc.15.29.
German (Pape)
[Seite 408] Ausruf des Staunens, vah! im N. T. auch des Abscheues, οὐὰ σοί, Matth. 11, 21; vgl. D. Cass. 63, 20; Arr. Epict. 3, 23.