Tense of pwn.
An internet chat language variety/version of the word "owned", used in the sence of beating/defeating/outclassing someone. Usually used in games such as Counter-strike or on messageboards when a user posts arguments or insults that can't possibly be counter-argued.
Arguably considered so-called "l33t-speak"
"I pwnd you that round" "You just got pwnd dude" "I am going to pwn you like I did your mother last night"