Death Penalty (also DP) is a penalty your character will gain every time in case you die and re-spawn. Death caused by participation in PvP however does not give you any DP. The system does not make you to loose your actual experiences, but forces you to remove your potential Death Penalty first before you start gaining new experiences. The amount of penalty is based on your highest level and it stacks up to 10 re-spawns. After that your Death Penalty stops growing. Minimal amount is 1 DP for level 1 (means 10 DP is maximum) and 462 500 DP for a level 250 master (means 4 625 000 is maximum).
In case you had to re-spawn and your character gained any Death Penalty, you need to remove it before you can gain any new experiences. The DP reduces itself slowly over the time and on low levels you might not even notice it. However with higher skills and repeated re-spawns, it might take few days before it wears off itself. Fortunately you have several ways how you can help to remove it:
Tip: Buy a service to speed up DP reduction when you if you are logging out and still have lots of DP yet to recover.
Visit following external links to learn more about amount of Death Penalty gained by your highest level: