It originated between 1910 and 1915 in the United States. One famous false etymology is that it stands for "without papers" or "without passport" (abbreviated WOP), widely known to be a fantasy derivation by acronym. According to Merriam-Webster its first known use was in 1908. The commonly accepted etymology is that it originates from a southern Italian dialect term guappo, meaning swagger, derived from the Spanish term guapo, via dialectical French, meaning ruffian or pimp. This also has roots in the Latin vappa, meaning wine gone flat. This theory holds that the term was brought to the U.S. by early Southern Italian immigrants from the region of Campania, who named those suspected to belonging to the Guapparia "Guappi", in a similar fashion Sicilian people used the term "Mafiosi". Widely used in Chicago where most immigrants from Campania settled, it was confused by non-Italian people to indicate Southern Italians in general, like the word "paesano".
Although the history of the word wop is not entirely certain, it can be found in various forms throughout pop culture. One memorable example is the bar fight scene in the film From Here to Eternity.