τερπνῶς

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

Russian (Dvoretsky)

τερπνῶς: радостно, в наслаждениях (τρέφειν τινά Soph.).