downheartedness vs low-spiritedness

downheartedness and low-spiritedness both are nouns.

Word	Noun	Adjective	Verb	Adverb
downheartedness	Yes	No	No	No
low-spiritedness	Yes	No	No	No

As nouns, downheartedness and low-spiritedness are synonyms defined as:

Other synonyms of downheartedness include dejectedness, dispiritedness, lowness.

downheartedness (noun)	low-spiritedness (noun)
a feeling of low spirits	a feeling of low spirits