A tragic flaw, in literature is the one problem an otherwise perfect protagonist (often called the tragic hero) has, that eventually brings him down in the end. The concept was created in ancient Greek tragedy. More often than not, the tragic flaw is hubris, such as in the works Antigone and Oedipus Rex. Another famous tragic hero is Shakespeare's King Lear. An example of a protagonist with a tragic flaw in modern literature would be Willy Loman in Death of a Salesman.
See: tragic hero
