matt vs dullness

matt and dullness both are nouns.

Word	Noun	Adjective	Verb	Adverb
matt	Yes	Yes	No	No
dullness	Yes	No	No	No

As nouns, dullness is a hypernym of matt; that is, dullness is a word with a broader meaning than matt:

matt: the property of having little or no contrast; lacking highlights or gloss
dullness: a lack of visual brightness

matt (noun)	dullness (noun)
the property of having little or no contrast; lacking highlights or gloss	lack of sensibility
	without sharpness or clearness of edge or point
	the quality of lacking interestingness
	a lack of visual brightness
	the quality of being slow to understand

matt (adjective)	dullness (adjective)
not reflecting light; not glossy