chemist vs Sir Robert Robinson

chemist and Sir Robert Robinson both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemist	Yes	No	No	No
Sir Robert Robinson	Yes	No	No	No

chemist (noun)	Sir Robert Robinson (noun)
a scientist who specializes in chemistry	English chemist noted for his studies of molecular structures in plants (1886-1975)
a health professional trained in the art of preparing and dispensing drugs