wither vs dry up

wither and dry up both are verbs.

Word	Noun	Adjective	Verb	Adverb
wither	No	No	Yes	No
dry up	No	No	Yes	No

As verbs, dry up is a hyponym of wither; that is, dry up is a word with a more specific, narrower meaning than wither:

Other hyponyms of wither include atrophy, blast, die back, die down, mummify.

wither (verb)	dry up (verb)
wither, as with a loss of moisture	lose water or moisture
lose freshness, vigor, or vitality	dry up and shrivel due to complete loss of moisture