κόπτεσθαι
From LSJ
πάντες γὰρ οἱ λαβόντες μάχαιραν ἐν μαχαίρῃ ἀπολοῦνται → all they that take the sword shall perish with the sword
Greek > English (Woodhouse Verbs Reversed)
(see also κόπτω): beat the breast, mourn for one dead, stamp money, strike a coin