long vs yearn

long is an adjective but yearn is not an adjective.

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

As verbs, long and yearn are synonyms defined as:

Other synonyms of long include hanker.

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

Other hyponyms of long include ache, languish, pine, yen.

long (adjective)	yearn (adjective)
good at remembering
primarily spatial sense; of relatively great or greater than average spatial extension or extension as specified
primarily temporal sense; being or indicating a relatively great or greater than average duration or passage of time or a duration as specified
(of speech sounds or syllables) of relatively long duration
holding securities or commodities in expectation of a rise in prices
having or being more than normal or necessary
planning prudently for the future
of relatively great height
involving substantial risk

long (verb)	yearn (verb)
desire strongly or persistently	desire strongly or persistently
	have a desire for something or someone who is not present
	have affection for; feel tenderness for

long (adverb)	yearn (adverb)
for an extended time or at a distant time
for an extended distance