What's Jewish? Anything that's not goyish. And if you don't know what goyish is, all it means is...not Jewish! Pretty simple, right?
The difference between the two can be very subtle, as explained in this hilarious video from Josh Healey. Remixing the classic bit by Lenny Bruce, Healey takes us on comedic trip from Mos Def to masturbation to God himself to see who comes out ahead in that age-old battle: Jewish vs. Goyish.