clerical vs clerk

clerical is not a noun while clerk is a noun.

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

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

clerical (adjective)	clerk (adjective)
of or relating to the clergy
of or relating to clerks
appropriate for or engaged in office work

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