The bodybuilder who slapped the hell out of a judge during a competition in Greece has been BANNED FOR LIFE ... by the biggest bodybuilding organization in the world ... TMZ Sports has learned.
As we previously reported, Giannis Magos -- aka Ioannis Magkos -- attacked one of the judges after losing the Diamond Cup during a competition in Athens on Nov. 27.
Now, the IFBB is slapping back -- delivering a "life expulsion" to Magos ... which is a big deal, considering the organization is connected to the biggest events in the sport .