ache vs yearn

ache is a noun but yearn is not a noun.

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

As verbs, ache and yearn are synonyms defined as:

ache and yearn: have a desire for something or someone who is not present

Other synonyms of ache include languish, pine, yen.

As verbs, yearn is a hypernym of ache; that is, yearn is a word with a broader meaning than ache:

Other hypernyms of ache include hanker, long.

ache (noun)	yearn (noun)
a dull persistent (usually moderately intense) pain

ache (verb)	yearn (verb)
have a desire for something or someone who is not present	desire strongly or persistently
be the source of pain	have a desire for something or someone who is not present
feel physical pain	have affection for; feel tenderness for