When someone says something perhaps cruel or unkind about someone, even if it's true, we would say that's " below the belt, " that's not playing by the rules, not being nice.
" Below the belt" is a common expression, and that usually means someone who is doing something in a competition or in a fight, especially in sports, that is illegal – that is not allowed.
“below the belt” 是一个常见的表达,通常指的是在比赛或争斗中, 特别是在体育比赛中, 有人做了不合法或不允许的事情。