ἀκατάβλητος
From LSJ
τοῖς πράγμασιν γὰρ οὐχὶ θυμοῦσθαι χρεών· μέλει γὰρ αὐτοῖς οὐδέν· ἀλλ' οὑντυγχάνων τὰ πράγματ' ὀρθῶς ἂν τιθῇ, πράξει καλῶς → It does no good to rage at circumstance; events will take their course with no regard for us. But he who makes the best of those events he lights upon will not fare ill.
English (LSJ)
ον,
A irrefragable, λόγος Ar.Nu.1229. II not to be thrown down, πύργοι Sch.E.Hec.1.