Opp is a old 80's refrace meaning other people's pussy it printed.from the song O.P.P

Ovine Progressive Pneumonia

"Other people's pussy" As in the pussy of others, belonging permanently or temporarily.

Permanently: the female's
Temporarily: The male's; as in the male's girlfriend

A common misspelling of the exclamation "oops!"

The stupid geeked up way of saying oops.

O is for other P is for people scratchin temples the other P not that simple
It's sorta like another way to call a cat a kitten
It's five little letters that are missin' here
You get on occassion at the other party
As a game 'n it seems I gotta start to explainin'
You ever had a girl and met her on a nice hello
You get her name and number and then you feelin' real mellow
You get home, wait a day, she's what you wanna know about
Then you call up and it's her girlfriend or her cousin's house
It's not a front, F to the R to the O to the N to the T
It's just her boyfriend's at her house

Many popular definitions of OPP include:
Other People's Property
Other People's Privates
Other People's Penis
Other People's Pussy

but in a VH1 presentation of the 100 Greatest Hip Hop Songs, Treach of Naughty by Nature states
"OPP can stand for anything, the first O is Other and the second P is People's but the last P can stand for anything."