Upselling is a sales technique where a salesperson encourages a customer to purchase a more expensive or upgraded product or service. Some common synonyms for the word upsell include cross-selling, upgrading, recommending, promoting, and suggesting. Cross-selling involves promoting complementary products or services to the customer. Upgrading refers to suggesting a better version of the product or service being purchased. Recommending involves offering suggestions for add-ons or upgrades. Promoting and suggesting refer to actively promoting or encouraging the customer to purchase additional products or services. These words are all commonly used in sales and marketing to increase revenue and improve customer satisfaction.