highjack vs seize

highjack is a noun but seize is not a noun.

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

As verbs, seize is a hypernym of highjack; that is, seize is a word with a broader meaning than highjack:

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

highjack (verb)	seize (verb)
take arbitrarily or by force	capture the attention or imagination of
	affect
	take into your hands deliberately
	take or capture by force
	hook by a pull on the line
	take possession of by force, as after an invasion
	take temporary possession of as a security, by legal authority
	seize and take control without authority and possibly with force; take as one's right or possession