This term has its origins in Japan, where Japanese perverts share a common addiction: They love dirty school girl's panties.
NOT, and I repeat NOT the same thing as a gay man who hasn't left the closet yet.
Closet pervert is a term generally used to describe creepy men who seem as though they're hiding a nasty (very nasty) fetish from the world.
Fujiki: That man is creepy.
Sarah: He must be a closet pervert.
closet pervert - noun - Ebisu on Naruto
Naruto: Ahhgg!! Why are you here?!