sales rep vs sales representative

sales rep and sales representative both are nouns.

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

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

sales rep and sales representative: 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 rep include salesperson.

sales rep (noun)	sales representative (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)