faintness vs indistinctness

faintness and indistinctness both are nouns.

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

As nouns, indistinctness is a hypernym of faintness; that is, indistinctness is a word with a broader meaning than faintness:

Other hypernyms of faintness include blurriness, fogginess, fuzziness, softness.

faintness (noun)	indistinctness (noun)
the quality of being dim or lacking contrast	the quality of being indistinct and without sharp outlines
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