crnački

1. black
   Gospel je nastao u crnačkim crkvama u Americi. — Gospel originated in black churches in America.

2. colloq. (of work) like a slave; very hard
   Ceo mesec sam radio crnački za malu platu. — I worked like a slave all month for a tiny wage.

Crnac and crnački are ordinary, neutral standard Serbian words; afroamerički specifically means African American. The expression raditi crnački rests on a stereotype and may be perceived as offensive.