1.Lit. [for a boxer] to strike an opponent below the belt. (An unfair blow.) The champ hit the contender below the belt and the crowd began to boo like fury.Fred was hit below the belt and suffered considerably.
2.Fig. to deal someone an unfair blow. That's not fair! You told them I was the one who ordered the wrong-size carpet. That's hitting me below the belt.Todd hit below the belt when he said it was all her fault because she had become ill during the trip.