ἐπανορθωτής
From LSJ
Τὸ νικᾶν αὐτὸν αὑτὸν πασῶν νικῶν πρώτη τε καὶ ἀρίστη. Τὸ δὲ ἡττᾶσθαι αὐτὸν ὑφ' ἑαυτοῦ πάντων αἴσχιστόν τε ἅμα καὶ κάκιστον. → Τo conquer yourself is the first and best victory of all, while to be conquered by yourself is of all the most shameful as well as evil
English (LSJ)
οῦ, ὁ,
A corrector, restorer, τοῦ κάμνοντος D.H.8.67; of writings, Gal.7.894; τῶν τρόπων, = Lat. corrector morum, D.C.54.30; also, = Lat. corrector civitatis, IG4.1417 (Epid.), 5(1).541 (Sparta), 7.91 (Megara).