carbon copy vs carbon

carbon copy and carbon both are nouns.

Word	Noun	Adjective	Verb	Adverb
carbon copy	Yes	No	No	No
carbon	Yes	No	No	No

As nouns, carbon copy and carbon are synonyms defined as:

carbon copy (noun)	carbon (noun)
a copy made with carbon paper	a copy made with carbon paper
	an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compounds
	a thin paper coated on one side with a dark waxy substance (often containing carbon); used to transfer characters from the original to an under sheet of paper