Woppin is a combined word madeshort for "What happened". Commonly used when you are zoned out and not listening. Sort of like "Huh?" But instead, "Woppin?"
Hey man, did you see what happened to Jake last night?
Woppin?
Man. I hate repeating myself!
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.