Do you mean "wop"? I have heard that this is an acronym for "without papers," or in other words, an illegal alien.
Shall we mention "cracker" or WASP?
WOP (pronounced "whop" does not come from "without papers (or pasasport)"
Instead, it comes from the adjective "guappo" which in the neopolitan accent is pronounced whop. In the south, i.e., that portion of the country that was under the dominion of the Kingdom of Two Sicilies "gua..." is indeed often given the spanish pronunciation. Just listen to Neopolitan songs about "guaglione" (boy). There is no doubt that "guappo" for "whop" is the correct provenienza.
Guappo -
1 camorrista...member of the Camorra.
2 hoodlum, tough
3 cocky, arrogant
4 garish, vulgar
divertiti!