From Longman Dictionary of Contemporary Englishbody buildingˈbody ˌbuilding noun [uncountable] DSOan activity in which you do hard physical exercise in order to develop big muscles —body builder noun [countable]
Examples from the Corpus
body building• Robert Crehan claims he was held down as the body building star repeatedly kicked him.• Pecs mad, this body building lot.• Shadow has devoted most of his 31 years to body building. 