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

1.
дешевый удар, нечестный прием
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.
Его комментарий о ее прошлых ошибках был дешевым ударом.
•
The politician took a cheap shot at his opponent's family.
Политик нанес дешевый удар по семье своего оппонента.