dehydration vs dryness

dehydration and dryness both are nouns.

Word	Noun	Adjective	Verb	Adverb
dehydration	Yes	No	No	No
dryness	Yes	No	No	No

As nouns, dryness is a hypernym of dehydration; that is, dryness is a word with a broader meaning than dehydration:

dehydration: dryness resulting from the removal of water
dryness: the condition of not containing or being covered by a liquid (especially water)

Other hypernyms of dehydration include waterlessness, xerotes.

dehydration (noun)	dryness (noun)
the process of extracting moisture	objectivity and detachment
dryness resulting from the removal of water	moderation in or abstinence from alcohol or other drugs
depletion of bodily fluids	the condition of not containing or being covered by a liquid (especially water)