The phrase "are the offing" typically means that something is likely to happen in the near future. Some antonyms for this could include "uncertain," "doubtful," or "unlikely." These words suggest that there is little chance of anything happening soon. Another antonym could be "past," meaning that the event has already occurred and is no longer in the future. Alternatively, "permanent" could be an antonym, suggesting that whatever is being referred to is not temporary or subject to change. These antonyms highlight the idea that "are the offing" implies a sense of impending or imminent action, which is not always the case.