Antonyms for "stock up" include "deplete," "consume," "use up," "run out," and "exhaust." While "stock up" implies accumulating a surplus or reserve, its antonyms denote the opposite - the gradual or sudden depletion of a resource or the complete exhaustion of it. For instance, instead of stocking up on groceries, you could opt to minimize food wastage by consuming what you already have in your pantry. Similarly, you could avoid running out of gasoline by refueling your car before your tank hits empty. The antonyms of "stock up" highlight the importance of responsible consumption and mindful utilization of resources.