1. One of great wealth and/or prosperity. Commonly an anonymous benefactor responsible for spectacular and bizarre donations. Will immediately demand the most expensive room in the establishment, even if it isn't the nicest one. (This derives from the notion of "picking up" expensive items).
2. A slang term for someone who isn't a genius. (i.e. slow to "pick up" a fact).
3. A cunt.
"Look at that pickup over there in his solid gold hat. Who does he think he is?"
"You're a right pickup."