Slate examines the New York Post's apparent fascination with "perv" as a headline word. "Fiend" is also popular.
The examples mentioned in the Slate article don't include the one I use in my editing class when discussing libel:
Vatican sacks six pervy N.Y. priests
Here's the catch: Two of the priests were convicted of sex crimes; the others were punished by the Catholic Church for unknown reasons under the Charter for the Protection of Children and Young People. Yet the Post lumped them together as pervs.