Is it possible to call a person with black skin "nigga" if he came from Africa?

It's possible to call a golf ball a rocking chair, if you're so inclined. What's your point?

About black person?

No, unless you want to be a hateful person.

Possible? Yes.

Normal and/or socially acceptable? No.

It is always possible -- but it is also possible (and very highly possible) for you to get a punch in the face as a result.

You asked if it were possible. Yes, it's obviously possible. The real question is whether it's a good idea to do so. I kinda doubt it is. If you're so inclined, however, give it a try and let us know how it works out for you.

Is it possible to call an ignorant, racist bitch a bigot if she came from Russia?