flex vs cringe

flex and cringe both are nouns.

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

As verbs, cringe is a hyponym of flex; that is, cringe is a word with a more specific, narrower meaning than flex:

flex (noun)	cringe (noun)
the act of flexing	A posture or gesture of shrinking or recoiling.
	some event or object that causes embarrassment and shame

flex (verb)	cringe (verb)
cause (an object) to assume a crooked or angular form	show submission or fear
bend a joint	draw back, as with fear or pain
form a curve
contract
exhibit the strength of