There are a number of synonyms for the phrase "reminder of mortality," all of which convey a sense of the fragility and ephemerality of life. Some possible alternatives include "memento mori," "death knell," "death's shadow," "grim reaper," and "last breath." Each of these phrases calls to mind the idea that death is an inevitable and inescapable part of the human condition, and that life should therefore be cherished and lived to the fullest while we still have the chance. Whether contemplating our own mortality or that of others, these synonyms provide a powerful reminder of the ultimate fate that awaits us all.