A greeting made famous by Borat, a Kazakhi played by comedian Sascha Cohen. It is derived from the Hebrew "chhag sameachh", meaning "happy holiday", the traditional Jewish holiday greeting. Cohen is Jewish, and often parodies the unselfconscious stupidity of Borat's antisemitism, ironically adopting a Jewish greeting as Borat's generic greeting.
"Jagshemash, today we go to throwing the Jew down the well to save our country. Beware his teeth."