"Hike up" can be defined as "to increase or raise something, typically a price, quantity, or level." Some common antonyms for this phrase are "lower," "reduce," "decrease," "lessen," "minimize," and "diminish." These terms refer to actions that involve making something smaller, weaker, or less significant. For instance, a company could choose to lower their prices instead of hiking them up, or a manager might decide to reduce the workload of their employees instead of increasing it. The opposite of "hike up" can vary depending on the context, but it generally involves making something less rather than more.