διαπονητέον
From LSJ
Μεγάλοι δὲ λόγοι μεγάλας πληγὰς τῶν ὑπεραύχων ἀποτίσαντες γήρᾳ τὸ φρονεῖν ἐδίδαξαν → The great words of the arrogant pay the penalty by suffering great blows, and teach one to reason in old age
English (LSJ)
one must work hard at, Ph. 2.235.
Greek (Liddell-Scott)
διαπονητέον: ῥημ. ἐπίθ., πρέπει τις νὰ ἐργασθῇ πολύ, Κλήμ. Ἀλ. 284.
Spanish (DGE)
hay que esforzarse, practicar, ἐγκράτεια, ἣν ... δ. el autodominio que hay que practicar Ph.2.235, τὸ ἔντεχνον Clem.Al.Paed.3.10.51.