Stygius

From LSJ

οὐ γὰρ ἂν τό γε πραχθὲν ἀγένητον θείη → since he cannot make what was done as though it had not come to pass

Source

Latin > English (Lewis & Short)

Stygĭus: a, um, v. Styx, II. 1.

Latin > French (Gaffiot 2016)

Stўgĭus, v. Styx.