When atticus speaks of people being "trash," he's referring to

their appearance
the quality of their character
their lineage
their manners

When Atticus speaks of people being "trash," he's referring to the quality of their character.

Atticus talks about how some men carry their resentments into a jury box. Also, he mentions that white men cheat black men but "whenever a white man does that to a black man, no matter who he is, how rich he is, or how fine a family he comes from, that white man is trash.” Therefore, Atticus is describing that man's character and identity. He is not criticizing his manners, appearance or lineage but the essence of who he is.

evertheless he ought to be slow to believe and to act, nor should he himself show fear, but proceed in a temperate manner with prudence and humanity, so that too much confidence may not make him incautious and too much distrust render him intolerable.

explanation: