Definition: 'you're full of it', 'whatever' or 'you're not that cool'. Soap is a valuable item in jail. Having a good bar of soap makes you a bit cooler, better/luckier than the rest of the inmates.
"I don't know why it's taking him so long to hang that new front door, damn, I would be finished already!"

His friend: " Oh you think you can hang doors now hu..? Psssh. Ha. You Ain't Got No Soap. "
by Homer Sully. June 5, 2013
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