ache vs thirst

ache and thirst both are nouns.

Word	Noun	Adjective	Verb	Adverb
ache	Yes	No	Yes	No
thirst	Yes	No	Yes	No

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

Other hyponyms of ache include bite, burn, sting, burn, itch, hunger, act up, throb, shoot.

ache (noun)	thirst (noun)
a dull persistent (usually moderately intense) pain	strong desire for something (not food or drink)
	a physiological need to drink

ache (verb)	thirst (verb)
have a desire for something or someone who is not present	have a craving, appetite, or great desire for
be the source of pain	feel the need to drink
feel physical pain