Basically, a piece of shit car. Usually cheap and/or broken down. Can be any size, make or model, but must (or should) be embarrassing to drive for some reason, such as when you bump the stereo all the plastic "effects" you have hot-glued to the exterior rattle, instantly betraying the cheapness of your bling
A hoopty can be anything from a '78 Cadillac Brogham with the panels missing in front of the brake lights (but replaced on only one side with duct tape), to a fine purple two-year old Hyundai Elantra with three spinner hubcaps and a vanity plate that reads BBY GRL.
The term has also been used in certain circles as an insult to one's boy or girlfriend, as in scrub
or hoochie mama
1. Can you believe he be gettin' all mad whenever somebody lean up against his old stupid hoopty.
2. I can see now you ain't nothin' but a hoopty.