thirstiness vs waterlessness

thirstiness and waterlessness both are nouns.

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

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

thirstiness: a deficiency of moisture (especially when resulting from a permanent absence of rainfall)
waterlessness: the condition of not containing or being covered by a liquid (especially water)

Other hypernyms of thirstiness include dryness, xerotes.

thirstiness (noun)	waterlessness (noun)
strong desire for something (not food or drink)	the condition of not containing or being covered by a liquid (especially water)
a physiological need to drink
a deficiency of moisture (especially when resulting from a permanent absence of rainfall)