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

Source

French (Bailly abrégé)

adv.
à l'improviste.
Étymologie: ἀδόκητος.

Russian (Dvoretsky)

ἀδοκήτως: неожиданно (εὐτυχῆσαι Thuc.).

Spanish

inesperadamente

Lexicon Thucydideum

praeter opinionem, beyond expectation, 3.45.6, 4.17.4.