clench vs clutch

clench and clutch both are nouns.

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

As nouns, clench and clutch are synonyms defined as:

Other synonyms of clench include clasp, clutches, grasp, grip, hold.

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

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

clench (noun)	clutch (noun)
the act of grasping	the act of grasping
a small slip noose made with seizing	a coupling that connects or disconnects driving and driven parts of a driving mechanism
	a pedal or lever that engages or disengages a rotating shaft and a driving mechanism
	a woman's strapless purse that is carried in the hand
	a collection of things or persons to be handled together
	a number of birds hatched at the same time
	a tense critical situation

clench (verb)	clutch (verb)
hold in a tight grasp	affect
squeeze together tightly	take into your hands deliberately
	hold firmly, usually with one's hands