chemist vs Sir William Crookes

chemist and Sir William Crookes both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemist	Yes	No	No	No
Sir William Crookes	Yes	No	No	No

chemist (noun)	Sir William Crookes (noun)
a scientist who specializes in chemistry	English chemist and physicist; discovered thallium; invented the radiometer and studied cathode rays (1832-1919)
a health professional trained in the art of preparing and dispensing drugs