suqlched up form of the word "Joke", usually used in MMO by cooldewds or AZN style slang. (keke, ^^, etc)
Usually shorting up "Is this a joke?" with the words "Is Jok?"
me: "I just camped boosmob xy and got PK´ed by A$$mastah right when it spawned".
cooldewd: "Is Jok ??"