Honor manifest in Othello in several ways. Some are positive; some are not. Othello faces the charges Brabantio hurls against him openly and in public, in part because of his honor. This leads him to honorable action. On the other hand, Othello's offended honor, with his sense that Desdemona has cheated on him, is part of what drives him to kill her. A third position on honor is Iago's. When he is talking to Roderigo, Iago tells him that virtue (and by extension honor) are meaningless. What matters is the ability to get what you want.