carmaker vs auto maker

carmaker and auto maker both are nouns.

Word	Noun	Adjective	Verb	Adverb
carmaker	Yes	No	No	No
auto maker	Yes	No	No	No

As nouns, carmaker and auto maker are synonyms defined as:

carmaker and auto maker: a business engaged in the manufacture of automobiles

Other synonyms of carmaker include auto manufacturer, automaker, car maker, car manufacturer.

carmaker (noun)	auto maker (noun)
a business engaged in the manufacture of automobiles	a business engaged in the manufacture of automobiles