ποιητέον

From LSJ

ἡ γὰρ σιωπὴ τοῖς σοφοῖσιν ἀπόκρισιςsilence, you see, is an answer for the wise (Menander)

Source

German (Pape)

[Seite 648] adj. verb. von ποιέω, man muß machen, thun, Her. 1, 191 Plat. conv. 217 a u. sonst.