Ethnic cleansing is, according to a 1993 United Nations Commission, "the planned deliberate removal from a specific territory, persons of a particular ethnic group, by force or intimidation, in order to render that area ethnically homogenous."
The phrase ethnic cleansing often implies mainly physical removal rather than mass killings. Regardless, violence, threats of violence, and other crimes very often occur during ethnic cleansings. However, there is no international treaty that specifies a specific crime of ethnic cleansing, although recently some international courts have defined the forcible deportation of a population (not limited to ethnic groups) as a crime against humanity.
Examples of argued ethnic cleansings include many in the Jewish Bible, of Jews during Jewish expulsions, Lebensraum during WWII, of Germans and others during and after WWII, and of Palestinians by Israel.
The phrase "ethnic cleansing" may sometimes be used as an ambiguous negative label on a wide variety of disliked phenomena involving changing ethnic demographics, such as colonialism, genocide, mass immigration, repatriation, and various forms of White flight.
- Ethnic Cleansing Law & Legal Definition http://definitions.uslegal.com/e/ethnic-cleansing/