crouch vs flex

crouch and flex both are nouns.

Word	Noun	Adjective	Verb	Adverb
crouch	Yes	No	Yes	No
flex	Yes	No	Yes	No

As verbs, flex is a hypernym of crouch; that is, flex is a word with a broader meaning than crouch:

Other hypernyms of crouch include bend.

crouch (noun)	flex (noun)
the act of bending low with the limbs close to the body	the act of flexing

crouch (verb)	flex (verb)
sit on one's heels	cause (an object) to assume a crooked or angular form
bend one's back forward from the waist on down	bend a joint
	form a curve
	contract
	exhibit the strength of