As nouns the difference between retail and tourer
is that retail
is the sale of goods directly to the consumer; encompassing the storefronts, mail-order, websites, etc, and the corporate mechanisms, branding, advertising, etc that support them, which are involved in the business of selling and point-of-sale marketing retail goods to the public while tourer
is (dated) an open-top or soft-top motor car suitable for touring.
As an adjective retail
is of, or relating to the (actual or figurative) sale of goods or services directly to individuals.
As an adverb retail
is direct to consumers, in retail quantities, or at retail prices.
As a verb retail
is to sell at retail, or in small quantities directly to customers.