ῥητορεύω
From LSJ
εἰς τετρημένον πίθον ἀντλεῖν → run water into a punctured pitcher, to the perforated jar bale water, labour in vain, labor in vain
English (LSJ)
A to be a public speaker, practise oratory, Isoc.Ep.8.7, Pl. Grg.502d, Arist.Rh.Al.1444a33; οἱ μετὰ γαστέρα -εύοντες afterdinner speakers, Ph.1.156; ῥ. καὶ πολιτεύεσθαι Chrysipp.Stoic.3.175; opp. πολιτεύεσθαι, Nausiph.2:—Pass., of the speech, to be spoken, τοὺς μὲν [λόγους] ῥητορεύεσθαι, τοὺς δὲ γεγράφθαι Isoc.5.25:—later in Act. c. acc., τὴν ἐπεσταλμένην πρεσβείαν ἐρρητόρευε was setting forth, Luc.Laps.2. II teach oratory, Str.14.1.48.