Banish, exile, expatriate, ostracize, deport, transport, extradite are comparable when denoting to remove by authority or force from a country, state, or sovereignty.
To banish is to compel one, usually by public edict or sentence, to leave a country or section, although not necessarily one’s own, either permanently or for a fixed time and with or without restriction to a given place.
To exile is to banish or cause to depart under constraint from one’s own country; it may connote either expulsion by formal sentence or decree or the compulsion of circumstances and an enforced absence or sometimes a prolonged voluntary absence; thus, Russians and foreigners alike may be banished from Russia, but only Russians can be exiled to Siberia; Dante was banished from his native Florence because of political troubles, but he exiled himself for the rest of his life as a protest against conditions there.
Expatriate differs from exile sometimes in its implication of loss of citizenship in one’s own country, but oftener in its implication of voluntary exile or naturalization in another country.
Exile often suggests a possibility of return with full rights to one’s own country; expatriate, however, may imply the exclusion of that possibility.
In historical context ostracize denotes a temporary banishment by popular vote from one of the cities of ancient Greece; the term is used more commonly in an extended sense which implies not expatriation, but a forced exclusion by common consent, from recognition or acceptance by society.
To deport is to send a person out of a country of which he is not a citizen either because his presence is considered inimical to the public welfare or because he has not lawfully entered that country. It often implies return to the country of which the deported person is a citizen or subject or from which he has emigrated, especially if he is without funds to go where he chooses. To transport is to banish to a penal colony a person convicted of a crime.
To extradite is to deliver over an alleged criminal at the request of the sovereignty or state having jurisdiction to try the charge.