The word "un-remembered" implies something that has been forgotten or not recalled. Its antonyms can be words like "remembered," "recalled," "retained," "recollected," and "memorized." When we remember something, it means that it is stored in our memory and we can easily retrieve it when needed. The opposite of this is to forget or not to remember. Therefore, if something is un-remembered, it is not recalled or retained in the memory. The presence of antonyms for such words helps us understand better the meaning of the original word and its usage in different contexts.