The word "un-memorable" refers to something that is not worth remembering or that does not leave a lasting impression. There are several antonyms for this term that describe the opposite. For example, "memorable" means that something is remarkable, impressive, or unforgettable. It can evoke strong emotions or leave a lasting impression on someone's memory. Other antonyms for "un-memorable" include "noteworthy," "remarkable," "memorable," "impressive," "unforgettable," and "notable." These words can be used to describe events or experiences that are significant, meaningful, or remarkable in some way, making them stand out in people's memories.