Words mean their definition. If someone defines nigger differently from you that's how they will interpret it. That's why we have dictionary, so everyone has the same definition and there is no confusion as to their meaning.
http://dictionary.reference.com/browse/nigger
–noun
1. Slang: Extremely Disparaging and Offensive.
a. a black person.
b. a member of any dark-skinned people.
2. Slang: Extremely Disparaging and Offensive. a person of any race or origin regarded as contemptible, inferior, ignorant, etc.
3. a victim of prejudice similar to that suffered by blacks; a person who is economically, politically, or socially disenfranchised.
Obviously the dictionary is not much help in this instance. Best not to use the word at all.