Greg is someone who will talk a girl up and then use her. known to sleep with girls and then date them for a few months only to find another girl to call her and bitch her out. He usually likes it in the ass and is a cowardly pussy.
a boy who likes a girl, doesn't tell her, then she likes him and he stops talking to her.
really dramatic and wants attention all the time.
exactly like the word gregarious!
"Whatever happened to that guy you liked?"
"Oh.. he turned into a greg..."