Compressed phrase that means "Did you eat?" often heard as "Jew eat?" by particularly sensitive and/or peculiarly paranoid people of the Jewish persuasion, especially when asked by a goy (non-Jew). "Jew eat?" syndrome was first exposed to mass culture by Woody Allen in his Oscar-winning film "Annie Hall" (1977).
Alvy Singer (Woody Allen) to his calm friend Rob (Tony Roberts):
"You know, I was having lunch with some guys from NBC, so I said, 'Did you eat yet or what?' And Tom Christie said, 'No, JEW?' Not 'Did you?'...JEW eat? JEW? You get it? JEW eat?"
-- Woody Allen, screenplay for "Annie Hall"