ἄκλαυτος
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)
or ἄκλαυστος (the latter form has less Ms. authority), ον: (κλαίω): I Pass., unwept, esp. without funeral lamentation, Il.22.386, Od.11.54, Sol.21; ὤλετ' ἄκλαυτος, ἄϊστος A.Eu.565: c. gen., φίλων ἄκλαυτος S.Ant.847: in E.Andr.1235 Thetis says, ἐγὼ γάρ, ἣν ἄκλαυτα χρῆν τίκτειν τέκνα... i.e. children not liable to death. II Act., unweeping, tearless, οὐδέ σέ φημι δὴν ἄκλαυτον ἔσεσθαι Od.4.494, cf.A.Th.696, E.Alc.173:—in S.El.912, = χαίρων, with impunity.
German (Pape)
[Seite 73] Hom. viermal, Iliad. 22, 386 κεῖται πὰρ νήεσσι νέκυς ἄκλαυτος ἄθαπτος, unbeweint; Od. 11, 54 σῶμα γὰρ κατελείπομεν ἡμεῖς ἄκλαυτον καὶ ἄθαπτον; 72 μή μ' ἄκλαυτον ἄθαπτον ἰὼν ὄπιθεν καταλείπειν; – Od. 4. 494 οὐδέ σέ φημι δὴν ἄκλαυτον ἔσεσθαι, ἐπὴν εὗ πάντα πύθηαι, nicht weinend, thränenlos; – Soph. Ant. 847 φίλων ἄκλαυτος, von Freunden nicht beweint.