Green’s Dictionary of Slang

prevert n.

a pervert.

1972		B. Rodgers Queens’ Vernacular 165: homosexual [...] prevert (redneckese).
1973		S. Ace Stand On It (1979) 131: He said you were one of them sex fiends, a pre-vert.
1996		Eble Sl. and Sociability 43: Gril ‘an affectionate noun of address to another female’ playfully reverses the internal sounds of girl, much like deliberately pronouncing pervert with the second and third sounds reversed as prevert.
2000		T. Udo Vatican Bloodbath 80: I’m a goddam fucken cocksucking, shit stabbing, jism-gobbling hard-core homofuckensexual trasvestite fucken sexual fucken pre-vert.