What it means
Straight out of boxing. A hit below the belt is a foul, so in normal chat this means someone said or did something cheap, unfair, and way too personal. It's the kind of low blow that skips a fair fight and goes straight for the sore spot.
Usage examples
"Dragging her family into the row was below the belt and he knew it."
"Mocking his stutter during the debate was well below the belt."
"Bringing up his divorce in the meeting was well below the belt."
"They can argue all they like, but mocking her accent was below the belt."
"Saying he only got the job because of his dad was a bit below the belt, mate."
Where it comes from
It comes from boxing, where punches below the belt are illegal because they target a protected area and can seriously hurt. That ring rule slipped into everyday English, so now if a comment is below the belt, it means someone went dirty and crossed the line in an argument.
