ἀπροόπτως

From LSJ

ἐπεὰν νῶτον ὑὸς δελεάσῃ περὶ ἄγκιστρον, μετιεῖ ἐς μέσον τὸν ποταμόν, ὁ κροκόδειλος ἵεται κατὰ τὴν φωνήν, ἐντυχὼν δὲ τῷ νώτῳ καταπίνει → when he has baited a hog's back onto a hook, he throws it into the middle of the river, ... the crocodile lunges toward the voice of a squealing piglet, and having come upon the hogback, swallows it

Source

French (Bailly abrégé)

adv.
à l'improviste.
Étymologie: ἀπρόοπτος.

Russian (Dvoretsky)

ἀπροόπτως: неожиданно, внезапно Plut.

Spanish

inconscientemente, inesperadamente, sin prever las consecuencias, de improviso