shrink back vs squinch

shrink back is not a noun while squinch is a noun.

Word	Noun	Adjective	Verb	Adverb
shrink back	No	No	Yes	No
squinch	Yes	No	Yes	No

As verbs, squinch is a hypernym of shrink back; that is, squinch is a word with a broader meaning than shrink back:

Other hypernyms of shrink back include cringe, flinch, funk, quail, recoil, shrink, wince.

shrink back (noun)	squinch (noun)
	a small arch built across the interior angle of two walls (usually to support a spire)

shrink back (verb)	squinch (verb)
pull away from a source of disgust or fear	cross one's eyes as if in strabismus
	draw back, as with fear or pain
	crouch down