lowness vs downheartedness

lowness and downheartedness both are nouns.

Word	Noun	Adjective	Verb	Adverb
lowness	Yes	No	No	No
downheartedness	Yes	No	No	No

As nouns, lowness and downheartedness are synonyms defined as:

Other synonyms of lowness include dejectedness, dispiritedness, low-spiritedness.

lowness (noun)	downheartedness (noun)
the quality of being low; lacking height	a feeling of low spirits
a low or small degree of any quality (amount or force or temperature etc.)
a feeling of low spirits
a position of inferior status; low in station or rank or fortune or estimation