body blow

1. Sports. A blow delivered to the front of the torso above the waist in boxing.
2. A serious setback; a major disappointment.

An action that causes severe damage, as in This last recession dealt a body blow to our whole industry. This term comes from boxing, where since the 18th century it has been used to refer to a punch that is landing between the opponent's chest and navel. [c. 1900]