Kewl is the swedish word for describing something/someone funny.
Probably copied by random people who thinks it's pronounced 'cool' and then used it as if it meant 'cool'.
Later, people got annoyed of it and made themselves look like shitheads by defining it on Urbandictionary.com. The same people later gave this defination a thumb down because they felt offensed by it.
And even later, this defination got deleted and no one could read it any longer. But by then, no one cared.
Examples stated at lexin.com, just search for kewl.
Yes, I'm lazy.