brown vs brownness

brown and brownness both are nouns.

Word	Noun	Adjective	Verb	Adverb
brown	Yes	Yes	Yes	No
brownness	Yes	No	No	No

As nouns, brown and brownness are synonyms defined as:

brown (noun)	brownness (noun)
an orange of low brightness and saturation	an orange of low brightness and saturation

brown (adjective)	brownness (adjective)
(of skin) deeply suntanned
of a color similar to that of wood or earth

brown (verb)	brownness (verb)
fry in a pan until it changes color
make brown in color