以上单词均有流放或放逐的含义。exile指长期离开祖国或家乡，可是自愿的，如为执行公务、躲避危险、压迫等原因；也可以是一种强制性惩罚，作为刑罚，多有一定期限[1]。banishment 则指被流放或驱逐国境， 即流放国外，其常指丧失国籍, 永久被流放[2] ; 现也用于强迫离开（forcible removal)。deportation 主要是指将不受欢迎的外国人驱逐出境[3]。expatriation多指某人自愿称自己为他国公民而放弃对祖国的效忠；用作流放时[4]，则指强迫某人离开祖国且使其放弃国籍。relegation可指罗马法中的放逐，类似流放刑，但比流放刑轻，被放逐者仍可保持其公民权；在英格兰，也多指暂时的司法放逐[5]。

[1] "Expulsion from a country，esp. from the country of one's origin or longtime residence. ” Cf. Bryan A. Gamer, Black's Law Dictionary, 7th edition, at p. 595, West Group (1999).
[2] "Expulsion from a nation； loss of nationality. " Cf. Daphne A. Dukelow, The Dictionary of Canadian Law, at p. 82，Thomson Professional Publishing Canada (1991).
[3] "The removal under this Act of a person from any place in Canada to the place whence he came to Canada or to the country of his nationality or citizenship or to the country of his birth or to such country as may be approved by the Minister under this Act，as the case maybe.” Cf. Immigration Act, R. S. C. 1970，c. 1-2, s. 2.
[4]“The voluntary act of abandoning or renouncing one's country, and becoming the citizen or subject of another. ”Cf. The Publisher's Editorial Staff, Black's Law Dictionary, abridged 6 th edition，at p. 399, West Publishing Co. (1991).
[5]“Banishment or exile, esp. a temporary one. ”Cf. Bryan A. Gamer, Black's Law Dictionary, 7th edition, at p. 1293，West Group (1999).