writer vs Robert W. Service

writer and Robert W. Service both are nouns.

Word	Noun	Adjective	Verb	Adverb
writer	Yes	No	No	No
Robert W. Service	Yes	No	No	No

writer (noun)	Robert W. Service (noun)
writes (books or stories or articles or the like) professionally (for pay)	Canadian writer (born in England) who wrote about life in the Yukon Territory (1874-1958)
a person who is able to write and has written something