hijack vs arrogate

hijack is a noun but arrogate is not a noun.

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

As verbs, arrogate is a hypernym of hijack; that is, arrogate is a word with a broader meaning than hijack:

hijack: seize control of
arrogate: seize and take control without authority and possibly with force; take as one's right or possession

Other hypernyms of hijack include assume, seize, take over, usurp.

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

hijack (verb)	arrogate (verb)
take arbitrarily or by force	seize and take control without authority and possibly with force; take as one's right or possession
seize control of	make undue claims to having
	demand as being one's due or property; assert one's right or title to