ostracismPronunciation: /ˈɒstrəsɪz(ə)m/Translate ostracism | into Italian Definition of ostracism noun [mass noun] 1exclusion from a society or group:the family suffered social ostracism 2(in ancient Greece) temporary banishment from a city by popular vote: the ostracism of Thucydidesostracism in other Oxford dictionaries Definition of ostracism in the US English dictionary