Craigslist acronym for NO PENIS PHOTOS used by people (mostly women looking for men) that don't want to have to spell it out for all the guys that like to email around pictures of their penis.
Quashon: Hot dang, wanna bangg??
Hannah: -throws up- Umm, no. -throws herself into a corner- I have NPP. NPP ALERT!!
Quashon: What's NPP??
Hannah: Something you have that I don't wanna see.