ostracism Syllabification: (os·tra·cism)Pronunciation: /ˈästrəˌsizəm/Translate ostracism | into Italian Definition of ostracism noun 1exclusion from a society or group:the family suffered social ostracism 2(in ancient Greece) temporary banishment from a city by popular vote. ostracism in other Oxford dictionaries Definition of ostracism in the British & World English dictionary