dehydration vs waterlessness

dehydration and waterlessness both are nouns.

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

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

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

Other hypernyms of dehydration include dryness, xerotes.

dehydration (noun)	waterlessness (noun)
the process of extracting moisture	the condition of not containing or being covered by a liquid (especially water)
dryness resulting from the removal of water
depletion of bodily fluids