faintheartedness vs faintness

faintheartedness and faintness both are nouns.

Word	Noun	Adjective	Verb	Adverb
faintheartedness	Yes	No	No	No
faintness	Yes	No	No	No

As nouns, faintheartedness and faintness are synonyms defined as:

faintheartedness and faintness: the trait of lacking boldness and courage

faintheartedness (noun)	faintness (noun)
the trait of lacking boldness and courage	the quality of being dim or lacking contrast
	barely audible
	the property of being without strength
	the trait of lacking boldness and courage
	a feeling of faintness and of being ready to swoon