sobriety vs earnestness

sobriety and earnestness both are nouns.

Word	Noun	Adjective	Verb	Adverb
sobriety	Yes	No	No	No
earnestness	Yes	No	No	No

As nouns, earnestness is a hypernym of sobriety; that is, earnestness is a word with a broader meaning than sobriety:

Other hypernyms of sobriety include serious-mindedness, seriousness, sincerity.

sobriety (noun)	earnestness (noun)
abstaining from excess	the trait of being serious
a manner that is serious and solemn	an earnest and sincere feeling
moderation in or abstinence from alcohol or other drugs
the state of being sober and not intoxicated by alcohol