πολύχρηστος
From LSJ
ἢ λέγε τι σιγῆς κρεῖττον ἢ σιγὴν ἔχε → either say something better than silence or keep silence (Menander)
English (LSJ)
ον,
A useful for many purposes, very useful, Arist.GA789b9, Pol.1337b26, Dsc. 1.1, Gal.6.534,480 (Sup.); τὸ π. Corn.ND9: Comp., Muson.Fr. 20p.112H., Alex.Aphr. in Top.277.4. Adv. -τως v.l. in Paul.Aeg.7.16.
German (Pape)
[Seite 677] sehr nutzbar, nützlich, Arist. gen. an. 5, 8.