The Collaborative International Dictionary of English v.0.48:
nigger \nig"ger\, n. A negro; -- in vulgar derision or depreciation. It is usually intended and interpreted as highly insulting and vulgar. [Low, deprecatory, and vulgar] [1913 Webster +PJC]WordNet (r) 3.0 (2006):
nigger n 1: (ethnic slur) extremely offensive name for a Black person; "only a Black can call another Black a nigga" [syn: nigger, nigga, spade, coon, jigaboo, nigra]