The phrase "on case" has several synonyms, including "investigating," "examining," "looking into," and "researching." These words are frequently used in the context of legal and financial matters, where it is important to thoroughly examine evidence and facts to determine the best course of action. Other synonyms for "on case" may include "pursuing," "solving," or "addressing," depending on the specific situation. Regardless of the word choice, the underlying meaning of "on case" is the same: actively working to resolve an issue or to achieve a particular goal.