To spend money to "improve" or "pimp out" a worthless item such as a crappy car, dump of a house, or other such item. Usually done by spending more to upgrade an item than was paid for it but still not actually increasing the value of the item with these upgrades.
After Sam spent $1900 to pimp out his $300 rusted out, beat up, 1982 Celebrity all he got for his trouble was a gilded turd and credit card debt.
"My sister is a moron."
"She bought a $30,000 burnt out house in the worst part of town and spent $100,000 making it livable. Now she can't sell it because everyone who could afford it doesn't want to live anywhere near that part of town."
"Sounds like she's got a gilded turd on her hands."