clerk vs penpusher

clerk and penpusher both are nouns.

Word	Noun	Adjective	Verb	Adverb
clerk	Yes	No	Yes	No
penpusher	Yes	No	No	No

As nouns, penpusher is a hyponym of clerk; that is, penpusher is a word with a more specific, narrower meaning than clerk:

clerk: an employee who performs clerical work (e.g., keeps records or accounts)
penpusher: a clerk who does boring paperwork

clerk (noun)	penpusher (noun)
an employee who performs clerical work (e.g., keeps records or accounts)	a clerk who does boring paperwork
a salesperson in a store

clerk (verb)	penpusher (verb)
work as a clerk, as in the legal business