'Shopper' definitions:

Definition of 'shopper'

From: WordNet
noun
Someone who visits stores in search of articles to buy
noun
A commercial agent who shops at the competitor's store in order to compare their prices and merchandise with those of the store that employs her

Definition of 'Shopper'

From: GCIDE
  • Shopper \Shop"per\, n. One who shops. [1913 Webster]