highjack vs carjacking

highjack and carjacking both are nouns.

Word	Noun	Adjective	Verb	Adverb
highjack	Yes	No	Yes	No
carjacking	Yes	No	No	No

As nouns, carjacking is a hyponym of highjack; that is, carjacking is a word with a more specific, narrower meaning than highjack:

highjack: seizure of a vehicle in transit either to rob it or divert it to an alternate destination
carjacking: the violent theft of an occupied car

highjack (noun)	carjacking (noun)
seizure of a vehicle in transit either to rob it or divert it to an alternate destination	the violent theft of an occupied car

highjack (verb)	carjacking (verb)
take arbitrarily or by force