draw in vs flex

draw in is not a noun while flex is a noun.

Word	Noun	Adjective	Verb	Adverb
draw in	No	No	Yes	No
flex	Yes	No	Yes	No

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

Other hypernyms of draw in include bend.

draw in (noun)	flex (noun)
	the act of flexing

draw in (verb)	flex (verb)
direct toward itself or oneself by means of some psychological power or physical attributes	cause (an object) to assume a crooked or angular form
draw in as if by suction	bend a joint
pull inward or towards a center	form a curve
of trains; move into (a station)	contract
advance or converge on	exhibit the strength of
shape one's body into a curl