writer vs William Sydney Porter

writer and William Sydney Porter both are nouns.

Word	Noun	Adjective	Verb	Adverb
writer	Yes	No	No	No
William Sydney Porter	Yes	No	No	No

writer (noun)	William Sydney Porter (noun)
writes (books or stories or articles or the like) professionally (for pay)	United States writer of short stories whose pen name was O. Henry (1862-1910)
a person who is able to write and has written something