im abit confused here, came into this late... i doubt he ment to be offensive, just like when people call me a injun or redskin, there not meaning to be offensive, there's also quite a few black i know myself here in washington that nigga isn't offensive to them where nigger is, but i think it pretty much depends on the person. Words can be a tricky game play, I would do as SAMS3D said, IM him and explain how its seen as a hurtful thing by you, be honest and upfront. I doubt he ment it to be a slur.