Something that you can never know anything about but believe everything you are told about it. Hoodilydaddle is a term given to anything you can't explain. It derives from things usually talked about by people in white lab coats. If you can't pronounce the name of certain things or topics just default to hoodilydaddle.
An automobile that has severe acute chronic problems with all aspects of its existence. Cosmetically the paint is poor, the seats are shitty, the suspension makes horrible noises. At any speeds above 55 a j-hoopidy complains like a jewish mother who just payed $12.50 to see The Passion of the Christ. Functionally the car works as transportation but as far as style points a jankedy-ass-hoopidy has none.
Fred's jankedy-ass-hoopidy is so rusty, stinky, and noisy its a wonder how he bags even a fat chick. Just breathe on his car wrong and the paint peels.