be below the belt

be below the belt

To unfairly target another person's weakness or vulnerability. The phrase refers to boxing, in which hitting an opponent below the waist is unacceptable. I know she really wants the promotion, but telling the boss about my personal problems was below the belt.
See also: below, belt

be below the belt

if something someone says is below the belt, it is cruel and unfair
Usage notes: In a boxing match it is wrong to hit the person you are fighting against below the belt.
It was below the belt to mention his brother's criminal record.
See also: below, belt