A grossly misused term assigned to any one male who pays too much attention to a specific female. Every girl you meet will tell you she has a creeper (why? Usually for a feeling of self-importance; if a girl doesn't have a 'creeper' who's completely obsessed with her then she might be seen by her fellow humans as a lesser being with no sexual appeal). The term is generally misused. You can be sure that the majority of creepers you hear about from your female friends are simply normal guys who may try to flirt with said female while she finds him unattractive or repulsive. The minority of creepers that you hear about may actually be desired by the female while she is simply too immature or afraid to admit her feelings for him thus dismissing him in such a fashion. Sometimes you literally need only comment on one of her photos on facebook for her to label you as a creeper for eternity.
"Oh em gee, Jared totally made eye-contact with me yesterday at that party. He's such a creeper!"
"Ugh, don't you just hate it when creepers are nice to you? Like the only reason they ask how your day has been is 'cause they want to have sex with you."
"Gill, I have like... Seven creepers right now, no joke. I guess I'm just super irresistible and hawt."