εὐθυκτέανον
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
English (LSJ)
ἰθὺ πεφυκυῖαν, εἰς ὀρθόν, Id. (-κτέσαν cod., cf. ἰθυκτέανον, εὐκτέανος.)
Greek (Liddell-Scott)
εὐθυκτέανον: (αἰτιατ. θηλ.)· «ἰθὺ πεφυκυῖαν, εἰς ὀρθὸν» Ἡσύχ.