shrivel vs atrophy

shrivel is not a noun while atrophy is a noun.

Word	Noun	Adjective	Verb	Adverb
shrivel	No	No	Yes	No
atrophy	Yes	No	Yes	No

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

Other hyponyms of shrivel include blast, die back, die down, dry up, mummify.

shrivel (noun)	atrophy (noun)
	any weakening or degeneration (especially through lack of use)
	a decrease in size of an organ caused by disease or disuse

shrivel (verb)	atrophy (verb)
wither, as with a loss of moisture	undergo atrophy
decrease in size, range, or extent