κακίζειν
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
Greek > English (Woodhouse Verbs Reversed)
(see also κακίζω): abuse, break down, make cowardly, speak evil of