deep brown vs umber

deep brown and umber both are nouns.

Word	Noun	Adjective	Verb	Adverb
deep brown	Yes	No	No	No
umber	Yes	Yes	No	No

As nouns, deep brown and umber are synonyms defined as:

Other synonyms of deep brown include burnt umber, chocolate, coffee.

deep brown (noun)	umber (noun)
a medium brown to dark-brown color	a medium brown to dark-brown color
	an earth pigment

deep brown (adjective)	umber (adjective)
	of the color of any of various natural brown earth pigments