Forgetting is a natural occurrence in our day-to-day life. At times, we might be unable to remember something important, and that could be frustrating. However, there are different ways to describe this inability to recollect information. One such synonym is "blank out," which means to forget something completely. Another synonym is "draw a blank," which is similar to blank out, but it focuses more on the act of trying to remember. We might also use "slip one's mind," which means to forget something that we should have remembered. Other synonyms for "be unable to remember" include "fail to recall," "lose track of," "omit," and "not retain".