Rebate is a term that refers to a type of discount or refund offered on a purchased product or service. Some possible antonyms for this term could include: markup, premium, surcharge, overcharge, or full price. If a business is marking up the price of a product, they are essentially adding an extra charge on top of the original cost rather than offering a discount. Similarly, a premium is an additional fee or cost attached to a service or product. A surcharge is another type of extra charge, often added on in order to cover unexpected costs or expenses. Overcharging refers to charging more than the fair or reasonable price, while not offering a rebate or discount. Finally, full price would be the opposite of a rebate, indicating that the buyer is paying the full cost of the product or service without any discount or reduction.