нерасторжимый
From LSJ
Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
Russian > Greek
ἀδιάλυτος, ἀκατάλυτος, ἄλυτος, δύσλυτος, δυσεξήνυστος, δυσδιάλυτος