exhaustion vs weariness

exhaustion and weariness both are nouns.

Word	Noun	Adjective	Verb	Adverb
exhaustion	Yes	No	No	No
weariness	Yes	No	No	No

As nouns, weariness is a hypernym of exhaustion; that is, weariness is a word with a broader meaning than exhaustion:

exhaustion: extreme fatigue
weariness: temporary loss of strength and energy resulting from hard physical or mental work

Other hypernyms of exhaustion include fatigue, tiredness.

exhaustion (noun)	weariness (noun)
the act of exhausting something entirely	temporary loss of strength and energy resulting from hard physical or mental work
serious weakening and loss of energy
extreme fatigue