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
το άγγελος
1. αγγελάκι, μικρός άγγελος
2. ωραίο και χαριτωμένο βρέφος.