scriptwriter vs author

scriptwriter and author both are nouns.

Word	Noun	Adjective	Verb	Adverb
scriptwriter	Yes	No	No	No
author	Yes	No	Yes	No

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

scriptwriter: someone who writes scripts for plays or movies or broadcast dramas
author: writes (books or stories or articles or the like) professionally (for pay)

Other hypernyms of scriptwriter include writer.

scriptwriter (noun)	author (noun)
someone who writes scripts for plays or movies or broadcast dramas	writes (books or stories or articles or the like) professionally (for pay)
	someone who originates or causes or initiates something

scriptwriter (verb)	author (verb)
	be the author of