The phrase "down with" is a commonly used expression that is often used to express a strong dislike or opposition to something or someone. However, there are many synonyms that you can use instead to convey your message more effectively. Some of these synonyms include "against," "opposed to," "disapproved of," "anti," and "hostile to." Other alternatives to "down with" can be "not in favor of," "in opposition to," "rejecting," and "detesting." It is important to choose the right synonym that fits the context of your message so that you can clearly express your feelings and thoughts.