What does it mean when a guy gives you contact while he is walking past you?
It probably means something caught his eye, maybe the way you were dressing stuck out that day, or maybe your hair was crazy, or maybe he thought you looked good. Really though, it doesn't mean a thing. It's just a look, people look at people all the time.
He could just be looking for no reason, you could have something in your teeth, he could think you're pretty, he could be doing anything, really..
It might not mean anything.
He's checkin out a booger in your nose. He is wishing you would talk to him because he doesn't have the courage to talk to you first.