The act of causing the death of another gamer's avatar in a virtual world, often in defiance of the world's normal rules of conduct or in spite of preventative code. Often abbreviated "PK," serving as a verb, a noun, or even an adjective describing certain players or game rule sets.
The phrase most likely arose in the development of early MUDs in the 1980's where game administrators waged a continuous struggle with players bent on defying in-game authorities and their rules, regardless of the repercussions to the games' stability.

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