below the belt
US /bɪˈloʊ ðə bɛlt/
UK /bɪˈloʊ ðə bɛlt/

1.
비열한, 불공평한, 개인적인 공격
unfair or cruel, especially in a way that is too personal
:
•
His comment about her past was really below the belt.
그녀의 과거에 대한 그의 언급은 정말 비열했다.
•
That joke was a bit below the belt, don't you think?
그 농담은 좀 비열했어, 그렇게 생각 안 해?