crouch vs scrunch up

crouch is a noun but scrunch up is not a noun.

Word	Noun	Adjective	Verb	Adverb
crouch	Yes	No	Yes	No
scrunch up	No	No	Yes	No

As verbs, crouch and scrunch up are synonyms defined as:

Other synonyms of crouch include hunker, hunker down, scrunch, squat.

crouch (noun)	scrunch up (noun)
the act of bending low with the limbs close to the body

crouch (verb)	scrunch up (verb)
sit on one's heels	make wrinkles or creases on a smooth surface; make a pressed, folded or wrinkled line in; `crisp' is archaic
bend one's back forward from the waist on down	sit on one's heels