sales representative vs sales rep

sales representative and sales rep both are nouns.

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

As nouns, sales representative and sales rep are synonyms defined as:

sales representative and 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 synonyms of sales representative include salesperson.

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