Someone who is not very talented at something, but is very easy to teach. For example, a player that is not good at baseball but listens and pays close attention to their coach and learns easily.
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.