shrink back vs quail

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

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

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

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

shrink back (noun)	quail (noun)
	small gallinaceous game birds
	flesh of quail; suitable for roasting or broiling if young; otherwise must be braised

shrink back (verb)	quail (verb)
pull away from a source of disgust or fear	draw back, as with fear or pain