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From LSJ

τραχὺς ἐντεῦθεν μελάμπυγός τε τοῖς ἐχθροῖς ἅπασιν → he is a tough black-arse towards his enemies, he is a veritable Heracles towards his enemies

Source

Russian > Greek

θρασύστομος, ἀπτοεπής, θρασύμυθος