knock off vs pen

knock off is not a noun while pen is a noun.

Word	Noun	Adjective	Verb	Adverb
knock off	No	No	Yes	No
pen	Yes	No	Yes	No

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

Other hypernyms of knock off include compose, indite, write.

knock off (noun)	pen (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

knock off (verb)	pen (verb)
stop pursuing or acting	produce a literary work
get rid of (someone who may be a threat) by killing
write quickly
take by theft
cut the price of