highjacking vs hijacking

highjacking and hijacking both are nouns.

Word	Noun	Adjective	Verb	Adverb
highjacking	Yes	No	No	No
hijacking	Yes	No	No	No

As nouns, highjacking and hijacking are synonyms defined as:

highjacking and hijacking: robbery of a traveller or vehicle in transit or seizing control of a vehicle by the use of force

highjacking (noun)	hijacking (noun)
robbery of a traveller or vehicle in transit or seizing control of a vehicle by the use of force	robbery of a traveller or vehicle in transit or seizing control of a vehicle by the use of force