brain surgeon vs neurosurgeon

brain surgeon and neurosurgeon both are nouns.

Word	Noun	Adjective	Verb	Adverb
brain surgeon	Yes	No	No	No
neurosurgeon	Yes	No	No	No

As nouns, brain surgeon and neurosurgeon are synonyms defined as:

brain surgeon and neurosurgeon: someone who does surgery on the nervous system (especially the brain)

brain surgeon (noun)	neurosurgeon (noun)
someone who does surgery on the nervous system (especially the brain)	someone who does surgery on the nervous system (especially the brain)