Klaus Fuchs vs physicist

Klaus Fuchs and physicist both are nouns.

Word	Noun	Adjective	Verb	Adverb
Klaus Fuchs	Yes	No	No	No
physicist	Yes	No	No	No

Klaus Fuchs (noun)	physicist (noun)
British physicist who was born in Germany and fled Nazi persecution; in the 1940s he passed secret information to the USSR about the development of the atom bomb in the United States (1911-1988)	a scientist trained in physics