Noun. A combination of gas and retard.
Somone who drives a giant, fuel inefficient SUV then has the balls to complain about paying $400 a week to keep it gassed up. Often seen with a "Gas Prices Suck" bumper sticker.
Gastard: Something needs to be done about this, I just spent $110 to fill up my Escalade.
Smart person: maybe you should buy a car with better milage.
Gastard: but I NEED! my hulking status symbol!
Smart Person: Gastard