The antonyms for the term "hot seller" can be varied, depending on the context in which it is used. In general, some antonyms for this term may include "unsold," "stale," "outdated," "obsolete," or "unpopular." These words describe items that are not in high demand, either due to their age, quality, or general lack of interest among consumers. On the other hand, these terms may also refer to items that have not yet sold well, implying that they are not likely to become popular in the near future. Therefore, if an item is described as an antonym of "hot seller," it may not be a great investment or purchase decision.