Here's what it means:
- Hanged: This means to be executed by hanging from a rope until dead.
- Drawn: This means to be dragged on a hurdle (a type of sled) to the place of execution.
- Quartered: This means to be cut into four pieces while still alive.
So, to be sentenced to be hanged, drawn, and quartered was a particularly gruesome form of execution that was reserved for traitors and other serious criminals in England until the 19th century.