John Philip Marquand vs writer

John Philip Marquand and writer both are nouns.

Word	Noun	Adjective	Verb	Adverb
John Philip Marquand	Yes	No	No	No
writer	Yes	No	No	No

John Philip Marquand (noun)	writer (noun)
United States writer who created the Japanese detective Mr. Moto and wrote other novels as well (1893-1960)	writes (books or stories or articles or the like) professionally (for pay)
	a person who is able to write and has written something