1. Originally from Greek drama, tragedy refers to the misery and fall of a potentially great figure because of a flaw ("tragic flaw") that is actually the flip side of what is originally his great strength.
2. In common use nowadays people just use it as a fancy word for "sad".
1. Annakin Skywalker's ambition and skill could have made him the galaxy's greatest Jedi and balancer of the Force, but it led him to the Dark Side and his tragic end as Darth Vader.
2. Giants fans mourned the tragic loss of the World Series last year.