buff vs yellowish brown

buff and yellowish brown both are nouns.

Word	Noun	Adjective	Verb	Adverb
buff	Yes	Yes	Yes	No
yellowish brown	Yes	No	No	No

As nouns, buff and yellowish brown are synonyms defined as:

Other synonyms of buff include caramel, caramel brown, raw sienna.

buff (noun)	yellowish brown (noun)
an implement consisting of soft material mounted on a block; used for polishing (as in manicuring)	a medium to dark tan color
a medium to dark tan color
bare skin
an ardent follower and admirer
a soft thick undyed leather from the skins of e.g. buffalo or oxen

buff (adjective)	yellowish brown (adjective)
of the yellowish-beige color of buff leather

buff (verb)	yellowish brown (verb)
polish and make shiny
strike, beat repeatedly