clench vs seize

clench is a noun but seize is not a noun.

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

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

Other hypernyms of clench include clutch, prehend, take hold, take hold of.

clench (noun)	seize (noun)
the act of grasping
a small slip noose made with seizing

clench (verb)	seize (verb)
hold in a tight grasp	capture the attention or imagination of
squeeze together tightly	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