The word “paddy” was once an ethnic slur. It was in reference to Irish immigrants who got drunk and stupid on the streets of New York, right off the Ellis Island potato boats. The cops would go out in big trucks and collect them, and they called those trucks “paddy wagons”. And that phrase still lingers in the American lexicon. Is this a great country, or what?
The Paddy Wagon got its name from Irishmen, often referred to as Paddies- or Padraigs- Irish for Patrick.