dimness vs faintness

dimness and faintness both are nouns.

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

As nouns, dimness and faintness are synonyms defined as:

dimness (noun)	faintness (noun)
the property of lights or sounds that lack brilliance or are reduced in intensity	the quality of being dim or lacking contrast
the quality of being dim or lacking contrast	barely audible
the state of being poorly illuminated	the property of being without strength
	the trait of lacking boldness and courage
	a feeling of faintness and of being ready to swoon