At the beginning of Chapter 9, Scout starts a fight with Cecil Jacobs for saying that Atticus "defended niggers" (85). She didn't even know what he meant, but she understood from his tone that he meant it as an insult. We also learn, in the ensuing conversation between her and Atticus, that "'s what everybody at school says." This reflects, largely, the town's disapproval of Atticus's taking Tom Robinson's case because he is black; they are clearly under the impression that black people need no lawyer in court and any lawyer who takes the case is less of a man for doing it. The next time she encounters Cecil in the schoolyard, he says, "My folks said your daddy was a disgrace an' that nigger oughta hang from the watertank!" (87).
At Christmas, we learn that their cousin Francis called Atticus a "nigger-lover" and that "Atticus'd be the ruination of the family" (98) which had provoked Scout to fight him and get into trouble with Uncle Jack.
Further, when Scout and Jem were passing Mrs. Dubose's house one day, she said that not only would Scout end up waiting on tables (because of how she dressed), but there was a Finch "in the courthouse lawing for niggers!" (117). Jem cracked from this, snatched Scout's new baton, and used it to knock the head off every camellia in Mrs. Dubose's yard.
After Atticus lost the case but humiliated Bob Ewell on the stand, Ewell allegedly spat tobacco juice on Atticus and said, "Too proud to fight, you nigger-lovin' bastard?" (248).
Later, in Aunt Alexandra's ladies' missionary society meeting, Mrs. Grace Merriweather implies that Atticus thought he was doing the right thing, but all he had done was "stir 'em up" (265). She also implies that blacks don't have the right to a fair trial, and the only real outcome was that people who--in her mind--should remain subservient got ideas that they deserved more rights than they already had.