The antonym for "am made known" can be "am hidden" or "am concealed". The word "antonym" refers to a word that has the opposite meaning of another word. When something is "made known", it is revealed or disclosed, and the opposite of that would be to hide or conceal it. For instance, if a person tells a secret to someone and asks them not to tell anyone, then the confidential information remains hidden or concealed from others. Similarly, if a company wants to keep its new product launch a secret, they will make sure to hide or conceal the details until the official announcement.