clerk vs paper-pusher

clerk and paper-pusher both are nouns.

Word	Noun	Adjective	Verb	Adverb
clerk	Yes	No	Yes	No
paper-pusher	Yes	No	No	No

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

clerk: an employee who performs clerical work (e.g., keeps records or accounts)
paper-pusher: a clerk or bureaucrat who does paperwork

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

clerk (verb)	paper-pusher (verb)
work as a clerk, as in the legal business