四字句英文該是甚麽表達?

an evil member of the herd; one who brings disgrace on his group; a rotten apple in the barrel; a black sheep; pests of society

害郡之馬你可以用:
an evil member of the herd,
one who brings disgrace on his group,
a rotten apple in the barrel,
a black sheep
又或者pests of sciety
全部都可以解做害郡之馬。