ἔχιδνα
From LSJ
ὅρκους γυναικὸς εἰς ὕδωρ γράφω → the oaths of a woman I inscribe on water, I write a woman's oaths in water
English (LSJ)
ἡ, (ἔχις)
A viper, Hdt.3.108, S.Tr.771, Pl.Smp.218a, etc.; prob. of a constrictor snake, Act.Ap.28.3: metaph., of a treacherous wife or friend, A.Ch.249, S.Ant.531; ἱματισμένη ἔ., of woman, Secund.Sent.8; γεννήματα ἐχιδνῶν brood of vipers, term of reproach, in Ev.Matt.3.7. II pr. n. of a monster, Hes.Th.297, S.Tr. 1099.