The concept of antonyms for "were one case" may be difficult to grasp, as "were one case" appears to be a specific phrase rather than a single word. However, one possible way to approach this is to consider antonyms for the individual words "were" and "one," which might change the meaning of the original phrase. Antonyms for "were," such as "weren't" or "didn't exist," could convey the opposite idea of something not being present or not having happened. Antonyms for "one" could include "many," "multiple," or "countless," indicating a larger or indefinite number of cases.