The Bedford Glossary of Critical and Literary Terms - Ross Murfin 2018
Tragic flaw: A character trait in a tragic hero or heroine that brings about his or her downfall. Although traits like arrogance or hubris (excessive pride) are common examples, a protagonist’s tragic flaw need not be “negative”; rather, it is simply the characteristic from which a reversal of fortune ensues. Thus, courage or generosity may equally be the trait whose expression leads to the direst of consequences.
The term tragic flaw is often used as a synonym for hamartia, but this usage is not strictly correct. Hamartia is more general, applicable to any error in judgment that brings about the protagonist’s downfall; tragic flaw refers specifically to an inherent character trait. Hamartia may result from a character’s tragic flaw but is not, technically speaking, the flaw itself. Rather, hamartia is the misstep or mistake that engenders the protagonist’s downfall and may thus include errors in judgment based on incomplete information regarding a situation as well as those based on character traits.