automobile vs motorcar

automobile and motorcar both are nouns.

Word	Noun	Adjective	Verb	Adverb
automobile	Yes	No	Yes	No
motorcar	Yes	No	No	No

As nouns, automobile and motorcar are synonyms defined as:

automobile and motorcar: a motor vehicle with four wheels; usually propelled by an internal combustion engine

Other synonyms of automobile include auto, car, machine.

automobile (noun)	motorcar (noun)
a motor vehicle with four wheels; usually propelled by an internal combustion engine	a motor vehicle with four wheels; usually propelled by an internal combustion engine

automobile (verb)	motorcar (verb)
travel in an automobile