The term "most long term" refers to something that lasts for a significant amount of time. Its antonyms can be "short term," "brief," or "temporary." Short term refers to something that lasts for a short duration, typically a few days or weeks. Brief implies something that is narrow, concise, and does not last for an extended period. Temporary means impermanent or not lasting, something that is expected to end soon. Therefore, the antonyms of "most long term" suggest a lack of permanence or a short lifespan. They signify a brief or short-lived nature, as opposed to something enduring and long-lasting.