a cheap shot
US /ə tʃiːp ʃɑt/
UK /ə tʃiːp ʃɑt/

1.
卑鄙的攻击, 不公平的言论
an unfair or unsporting remark or action, especially one made against a vulnerable person or at an opportune moment
:
•
His comment about her past mistakes was a cheap shot.
他对她过去错误的评论是卑鄙的攻击。
•
The politician took a cheap shot at his opponent's family.
这位政客对对手的家人进行了卑鄙的攻击。