ethnic cleansing

Possibly a calque of Serbo-Croatian etničko čišćenje, though this is probably attested later. Popularized by (and still often associated with) the wars in former Yugoslavia during the 1990s; however, versions of the phrase have been attested since the 1860s in various languages (with the earliest attestation translating directly to the phrase being Romanian purificare etnică from 1941) and it probably arose independently on numerous occasions.