A tragic hero is a major character in a situation who, usually through no fault of his own, has to "pass through a series of misfortunes leading to the final catastrophe." The hero has all the qualities of any hero, which may include character traits opening him/her up to the circumstances leading to his/her downfall. Often, however, the disastrous outcome is the result of natural or human events beyond the control of the hero or anyone else.
An example of a tragic hero could be Prince Hamlet. He is a strong character with a very strong and clear sense of duty which he is unable to fulfill due to circumstances beyond his control. His insanity is only one complicating factor in the overall story.
a tragic hero is someone with hubris and ends up getting defeated.