Marsh vs author

Marsh and author both are nouns.

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

Marsh (noun)	author (noun)
New Zealand writer of detective stories (1899-1982)	writes (books or stories or articles or the like) professionally (for pay)
United States painter (1898-1954)	someone who originates or causes or initiates something

Marsh (verb)	author (verb)
	be the author of