δυσεξίλαστος
From LSJ
εἰς πέλαγος σπέρµα βαλεῖν καὶ γράµµατα γράψαι ἀµφότερος µόχθος τε κενὸς καὶ πρᾶξις ἄκαρπος → throwing seeds and writing letters at sea are both a vain and fruitless endeavor
English (LSJ)
[ῑ], ον,
A hard to appease, πένθη Plu.2.609f.
German (Pape)
[Seite 679] schwer zu besänftigen; πένθη Plut. Consol ad ux. 6.