a cheap shot

US /ə tʃiːp ʃɑt/
UK /ə tʃiːp ʃɑt/
"a cheap shot" picture
1.

colpo basso, attacco sleale

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.
Il suo commento sui suoi errori passati è stato un colpo basso.
The politician took a cheap shot at his opponent's family.
Il politico ha sferrato un colpo basso alla famiglia del suo avversario.