прочный
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
Russian > Greek
ἐχυρός, παραμόνιμος, παρμόνιμος, ἐπιστατικός, κάτοχος, βέβαιος, ὀχυρός, ἰσχυρός, ἀμαιμάκετος, μόνιμος, ἀτειρής, ἔμμονος, δευσοποιός, ἔμπεδος, εὐπρυμνής, δυσραγής, καρτερός, ῥωμαλέος, συστατός, σύστατος, κραταιγύαλος, ἐμβριθής, εὐσταθής, ἐϋσταθής