by 1875, from genitive of sale + person.
WANTED, an experienced LADY ASSISTANT, good salesperson, for a Bookseller's and Stationer's Shop, with Library. Permanent to a suitable person. Apply W. PORTER and SONS, Herald Office, Blackpool. [advertisement in The Bookseller, May 4, 1875]
saleable
Salem
salep
salesman
salesmanship
salesperson
saleswoman
Salic
salience
saliency
salient