To carjack someone is to stop their car while they are in it and, with a weapon or a real threat, make them give you the car or drive you where you want. It is a crime, and you will hear the word mainly in news and police talk, not at the shops. People began using it in the United States in the 1990s, and British news uses it too now. Though actually, it is not the same as stealing a car that is sitting empty in the street — that is just stealing a car. With this word, the driver is right there. It is a verb: they carjacked him on the way home. Some reports stretch it a little, for any violent taking of a car at the roadside, even if nobody saw a gun; the hard centre of the word is still force, fear, and a driver who has not chosen to hand the car over.

劫車（持械逼司機交車或載你走；跟「劫機」的「劫」同一類）