μαστίω
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
English (LSJ)
[ῐ], poet. form of μαστίζω in pres. and impf.,
A whip, scourge, μάστιε νῦν Il.17.622, cf. Hes.Sc.466, Pancrat.Oxy.1085.15, Nonn.D. 1.179, al.:—Med., οὐρῇ δὲ πλευράς τε καὶ ἰσχία ἀμφοτέρωθεν μαστίεται Il.20.171.