Quoted from Frippertron:How did Marvel get away with the Deadpool character to begin with. He was a ripoff of DC's Deathstroke and to add insult to injury, Deathstroke's name is Slade Wilson and Deadpool's is Wade Wilson. Why didn't DC do anything? It's kind of funny how blatant the ripoff is.
It's almost like a total Deadpool move to rip off a character named Slade Wilson aka Deathstroke with a character named Wade Wilson aka Deadpool.