good speller vs writer

good speller and writer both are nouns.

Word	Noun	Adjective	Verb	Adverb
good speller	Yes	No	No	No
writer	Yes	No	No	No

As nouns, writer is a hypernym of good speller; that is, writer is a word with a broader meaning than good speller:

good speller (noun)	writer (noun)
someone who spells words	writes (books or stories or articles or the like) professionally (for pay)
	a person who is able to write and has written something