I agree with those who say that hamartia is best understood in its literal sense of "missing the mark" rather than as "tragic flaw." The two are different. Hamartia suggests an action—committing an error or misperceiving a situation—while "tragic flaw" suggests a condition, a state of being such as rashness or excessive egoism. Citing examples from Oedipus Tyrannus and King Lear, I show that in each case the protagonist's misperceptions exacerbate his flaw, serving to propel the action. Irony is shown to be frequently conjoined with hamartia. I argue that hamartia in Oedipus Tyrannus helps to effect catharsis.