ἀλλοιοῦσθαι
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
Greek > English (Woodhouse Verbs Reversed)
Lexicon Thucydideum
alienari, to become estranged, 2.59.1.