dejectedness vs sadness

dejectedness and sadness both are nouns.

Word	Noun	Adjective	Verb	Adverb
dejectedness	Yes	No	No	No
sadness	Yes	No	No	No

As nouns, sadness is a hypernym of dejectedness; that is, sadness is a word with a broader meaning than dejectedness:

Other hypernyms of dejectedness include unhappiness.

dejectedness (noun)	sadness (noun)
a feeling of low spirits	the quality of excessive mournfulness and uncheerfulness
	emotions experienced when not in a state of well-being
	the state of being sad