ἀπηγόρημα
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)
ατος, τό
A defence, opp. κατηγόρημα, Pl.Lg.765b.
German (Pape)
[Seite 290] τό, Verthe idigung, Ggstz κατηγόρημα Plat. Legg. VI, 765 b.