unhappiness vs emotional state

unhappiness and emotional state both are nouns.

Word	Noun	Adjective	Verb	Adverb
unhappiness	Yes	No	No	No
emotional state	Yes	No	No	No

As nouns, emotional state is a hypernym of unhappiness; that is, emotional state is a word with a broader meaning than unhappiness:

unhappiness: state characterized by emotions ranging from mild discontentment to deep grief
emotional state: the state of a person's emotions (especially with regard to pleasure or dejection)

Other hypernyms of unhappiness include spirit.

unhappiness (noun)	emotional state (noun)
emotions experienced when not in a state of well-being	the state of a person's emotions (especially with regard to pleasure or dejection)
state characterized by emotions ranging from mild discontentment to deep grief