ὀλεθρίως

From LSJ

εἰς τετρημένον πίθον ἀντλεῖν → run water into a punctured pitcher, to the perforated jar bale water, labour in vain, labor in vain

Source

Russian (Dvoretsky)

ὀλεθρίως: губительно, на погибель (χρῆσθαί τινι Plut.).