ἀδοκήτως
From LSJ
ἄλογον δὴ τὸ μήτε μάχης ἄρξασθαι μήτε τοὺς φίλους φυλάξαι, ἐὰν ὑπό γε τῶν βαρβάρων ἀδικῆσθε → It is irrational neither to begin battle nor to guard the friends, if you are ever wronged by the foreigners
French (Bailly abrégé)
adv.
à l'improviste.
Étymologie: ἀδόκητος.
Russian (Dvoretsky)
ἀδοκήτως: неожиданно (εὐτυχῆσαι Thuc.).