salesclerk vs sales rep

salesclerk and sales rep both are nouns.

Word	Noun	Adjective	Verb	Adverb
salesclerk	Yes	No	No	No
sales rep	Yes	No	No	No

As nouns, sales rep is a hypernym of salesclerk; that is, sales rep is a word with a broader meaning than salesclerk:

salesclerk: a salesperson in a store
sales rep: a person employed to represent a business and to sell its merchandise (as to customers in a store or to customers who are visited)

Other hypernyms of salesclerk include sales representative, salesperson.

salesclerk (noun)	sales rep (noun)
a salesperson in a store	a person employed to represent a business and to sell its merchandise (as to customers in a store or to customers who are visited)