hack writer vs author

hack writer and author both are nouns.

Word	Noun	Adjective	Verb	Adverb
hack writer	Yes	No	No	No
author	Yes	No	Yes	No

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

hack writer: a mediocre and disdained writer
author: writes (books or stories or articles or the like) professionally (for pay)

Other hypernyms of hack writer include writer.

hack writer (noun)	author (noun)
a mediocre and disdained writer	writes (books or stories or articles or the like) professionally (for pay)
	someone who originates or causes or initiates something

hack writer (verb)	author (verb)
	be the author of