hijack vs highjack

hijack and highjack both are nouns.

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

As nouns, hijack and highjack are synonyms defined as:

hijack and highjack: seizure of a vehicle in transit either to rob it or divert it to an alternate destination

As verbs, hijack and highjack are synonyms defined as:

Other synonyms of hijack include commandeer, pirate.

hijack (noun)	highjack (noun)
seizure of a vehicle in transit either to rob it or divert it to an alternate destination	seizure of a vehicle in transit either to rob it or divert it to an alternate destination

hijack (verb)	highjack (verb)
take arbitrarily or by force	take arbitrarily or by force
seize control of