I think for me it's a bass that costs more than it's worth to me in practical terms. I'm not a fancy player, and I like good, solid, un-showy workman-like tools (not just in the bass sphere, in life generally). I don't have a lot of disposable income so I tend to choose my purchases carefully. My main basses are both Fender Player P's, and I think they're a lot of bass for the money.
Therefore, I'd say that an American Original P would be what I'd say was expensive, as, nice as they are, they wouldn't offer a significant improvement in my hands, however much I might like one.