κατατεθαρρηκότως
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)
Adv. pf. part. Act. of καταθαρρέω,
A boldly, confidently, Plb.1.86.5, Plu.Ant.27.
