To carjack is to steal a car by hitting the victim's vehicle with another car, and then forcing the victim to get out of the car.(verb)
An example of to carjack is for a fleeing bank robber to hit a car at a red light and then run over to the car that was hit, demanding that the driver get out of the car, and then driving off with the damaged car.
See carjack in American Heritage Dictionary 4
or car-jacktransitive verb car·jacked or car-jacked, car·jack·ing or car-jack·ing, car·jacks or car-jacks
Origin: + (hi)jack.