nigga is English slang, used mainly among African Americans, and it means "black" or "black". This is considered a derogatory slang.
The word nigga is a derivative of nigger, a term that also means “black” or “black”, and its use is even more aggressive and pejorative.
As a rule, only African Americans can use the slang. nigga to refer to another person of black ethnicity, without the term taking on an even more offensive meaning. If someone of another skin color (a white, for example) call a black nigga, this act will be considered extremely offensive and may even be seen as a manifestation of racism.
Thus, in the United States, in some contexts, the slang nigga is taken as a bad word and is often censored with the expression "the N word" (the word with N, in Portuguese).
The explanation for the current negative interpretation of this word can be found during the period of slavery in the United States, when nigger it was used to refer to slaves as if they were inferior beings, that is, "sub-humans".
In Brazil, the slang nigga became popular through American movies and music, mainly of the genre rap music or hip hop. With the indexation of this foreign term in the daily lives of Brazilians, the nigga came to be used as a synonym for “negão” or “creole”.
Learn more about meaning of other slang.