ostracism

Concise Oxford English Dictionary © 2008 Oxford University Press:
ostracize /ˈɒstrəsʌɪz/ (or ostracise /ˈɒstrəsʌɪz/)

▶verb

• 1 exclude from a society or group.

• 2 (in ancient Greece) banish (a citizen) from a city for five or ten years by popular vote.

– derivatives
ostracism noun.

– origin C17: from Gk ostrakizein, from ostrakon ‘shell or potsherd’ (on which names were written in voting to banish unpopular citizens).