ἢ λέγε τι σιγῆς κρεῖττον ἢ σιγὴν ἔχε → either say something better than silence or keep silence (Menander)
γυμνάζω, ἐξασκέω, ἐγγυμνάζω, ἐμμελετάω, προσγυμνάζω, ἀπογυμνάζω, ἐνασκέω, ἀσκέω