sales demonstrator vs sales rep

sales demonstrator and sales rep both are nouns.

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

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

sales demonstrator: someone who demonstrates an article to a prospective buyer
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 sales demonstrator include sales representative, salesperson.

sales demonstrator (noun)	sales rep (noun)
someone who demonstrates an article to a prospective buyer	a person employed to represent a business and to sell its merchandise (as to customers in a store or to customers who are visited)