Basically it is the next "fuck" it can be used as a verb, an adjective, and a noun.
Verb: to beat, have sex with, over power, and/or "own"
Adjective: Awesome, 1337, and/or cool
noun: something that is awesome, 1337 and/or cool
Passed tence: pwnt
I pwnt j00 at that game.
Man i heard that she pwnt him!
You mean that pwn hacker?
That is pwn.