ἀπταίστως

From LSJ

ὃν οὐ τύπτει λόγος οὐδὲ ῥάβδος → if words don't get through, neither a beating will | if the carrot doesn't work, the stick will not work either | whom words do not strike, neither does the rod

Source

Russian (Dvoretsky)

ἀπταίστως: не спотыкаясь, т. е. уверенно, неуклонно (ἔρχεσθαι Plat.); плавно (διὰ θαλάσσης ἐπιθέειν Plut.).