The phrase "be in the offing" typically refers to an event or situation that is about to happen or is expected to occur in the near future. Antonyms for this phrase could include "far-fetched," meaning something that is unlikely to happen or is improbable. Another antonym could be "distant," indicating that the event or situation is far away in time or space. "Unforeseeable" could also be an antonym, suggesting that the event or situation is entirely unexpected and could not have been predicted. Overall, the antonyms for "be in the offing" all suggest a lack of immediacy, uncertainty, or a low probability of occurrence.