Needing an Ethnographic Eytomologist

As I was walking down the street, I came between two men having a conversation that I was able to overhear. The reason that I was able to over hear this conversation is because they were having it from opposites sides of Madison Avenue.

They were talking about --- and one gentleman said to the other, "No, I haven't seen --- since that n**** merc'd me."

I have no idea what this means.

Now Urban Dictionary provides two definitions, neither of which fit the above statement.

This is and will continue to bother me until I figure it out (or forget it).

Any help would be appreciated.