The name given to some fat dumbass who doesn't realize that he isn't cool and uses all of the words in this sentence trying to be cool (e.g. chill, laidback, late, sketch, etc.)
Also given to them as an insult even though they think that this new name for them makes them even cooler.
In this example, A: and B: are normal people and C: is the fatty.
A: "Hey look, there's that fat fuck over there."
B: "You know what's funny?"
A: "No, what?"
B: "Yo, Chill Laidback McL8ster!! What's up, my brutha!?"
C: "Yo dude! Things are pretty chill!"