author vs pen

author and pen both are nouns.

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

As verbs, pen is a hypernym of author; that is, pen is a word with a broader meaning than author:

Other hypernyms of author include compose, indite, write.

author (noun)	pen (noun)
writes (books or stories or articles or the like) professionally (for pay)	female swan
someone who originates or causes or initiates something	a writing implement with a point from which ink flows
	an enclosure for confining livestock
	a correctional institution for those convicted of major crimes
	a portable enclosure in which babies may be left to play

author (verb)	pen (verb)
be the author of	produce a literary work