umber vs deep brown

umber and deep brown both are nouns.

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

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

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

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

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