βλαυτίον
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)
τό, Dim. of foreg., Ar.Eq.889, Aristodem.8, AP6.293 (Leon.); βλαύρια in Hsch., Cyr.
German (Pape)
[Seite 448] τό, dim. zum vorigen, Ar. Equ. 886; Ath. VIII, 338 a; Leon. Tar. 10, 38 (VI, 293 Plan. 307).