various policies and practices with the effect and/or purpose of eliminating an unwanted group from a society or territory, as by genocide or forced migration, in order to create an ethnically homogenous, or supposedly "pure” society, area or state. Although no legal definition yet exists, "ethnic cleansing” has become a commonly used term in international legal writings, discourse and official documents.
Ethnic cleansing could be defined broadly and narrowly. Broader definitions identify eviction or expulsion on the basis of ethnic criteria. Some narrower definitions add specific characteristics, including the "systematic” or "illegal” nature of the evictions/expulsions, involving gross violations of human rights or grave breaches of international humanitarian law, or describe their context of an ongoing internal or international war, and/or deliberate policy. For example, another author characterizes ethnic cleansing is:
"a well-defined policy of a particular group of persons…systematically [to] eliminate another group from a given territory on the basis of religious, ethnic or national origin. Such a policy involves violence and is very often connected with military operations. It is to be achieved by all possible means, from discrimination to extermination, and entails violations of human rights and international humanitarian law.”
One author defines ethnic cleansing such that,
"At one end, it is virtually indistinguishable from forced emigration and population exchange while at the other it merges with deportation and genocide. At the most general level, however, ethnic cleansing can be understood as the expulsion of an “undesirable” population from a given territory due to religious or ethnic discrimination, political, strategic or ideological considerations, or a combination of these.
The term “ethnic cleansing” entered the English lexicon as a calque (loan translation) of the Serbo-Croatian/Bosnian phrase etničko čišćenje. In the early the 1990s journalists and news media used the term extensively in reporting on events in the former Yugoslavia, and it has since become popularized and used more generally to describe analogous situations. The term may have earlier antecedents in the military doctrine of the former Yugoslav People’s Army, which adopted the phrase “cleansing the field” (čišćenje terena); i.e., eliminating enemy presence, in order to gain total control of a conquered territory.
Ethnic cleansing does not have a legal definition. However, the term has been used in numerous legal texts, including UN documents.
A UN Commission of Experts on grave breaches and other violations of international humanitarian law in the former Yugoslavia defined the practice as "rendering an area ethnically homogeneous by using force or intimidation to remove persons of given groups from the area. `Ethnic cleansing’ is contrary to international law.”
In 1992, the UN General Assembly categorized "ethnic cleansing,” as then underway in Yugoslavia, as "a form of genocide.”
 Dražen Petrović, "Ethnic Cleansing – An Attempt at Methodology,” European Journal of International Law, Vol. No. 3, pp. 342–60, at 352, at: http://www.ejil.org/journal/Vol5/No3/art3.html and quoted in quoted by Ilan Pappe, The Ethnic Cleansing of Palestine” (Oxford: Oneworld Publications, 2006), p.1.
 Andrew Bell-Fialkoff, "A Brief History of Ethnic Cleansing,” Foreign Affairs, Vol. 72, No. 3 (summer 1993), at: http://www.foreignaffairs.org/19930601faessay5199/andrew-bell-fialkoff/a-brief-history-of-ethnic-cleansing.html.
 "Ethnic cleansing,” in Wikipedia, at: http://en.wikipedia.org/wiki/Ethnic_cleansing#_note-1.
 Interim Report of the Commission of Experts Established Pursuant to Security Council Resolution 780 (1992), para. 55.
 "The situation in Bosnia and Herzegovina,” General Assembly resolution A/RES/47/121, adopted at the 91st plenary meeting, 18 December 1992.