The phrase "were up and up" means to be honest, truthful, and reliable. Some possible antonyms for this expression could be dishonest, fraudulent, or deceitful. When someone is not up and up, they may be concealing information, lying, or manipulating the truth in some way. Other antonyms for "were up and up" might include insincere, unethical, or misleading. It's important to be aware of these potential opposites, as they can help us recognize when someone is behaving in a less-than-honest way and avoid being deceived. Overall, the antonyms for "were up and up" represent a lack of integrity and trustworthiness.