The phrase "ad interim" means "in the meantime" or "for the time being." Its antonyms are "permanent," "final," or "eternal." When we say something is ad interim, it means it is only temporary and will eventually change. Using antonyms of this phrase can indicate a more long-term or permanent situation. For example, instead of saying that someone is an ad interim manager, we can say that they are a permanent manager. Similarly, instead of a board making ad interim decisions, they make final or permanent decisions. The antonyms of ad interim can give us a more accurate understanding of a situation's nature and help us communicate more effectively.