pen vs compose

pen is a noun but compose is not a noun.

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

As verbs, pen and compose are synonyms defined as:

Other synonyms of pen include indite, write.

pen (noun)	compose (noun)
female swan
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

pen (verb)	compose (verb)
produce a literary work	make up plans or basic details for
	produce a literary work
	write music
	put together out of existing material
	calm (someone, especially oneself); make quiet
	form the substance of