Which term means to speak ill of or attack the character of someone?

The correct answer is denigrate, which specifically refers to the act of speaking ill of someone or attacking their character. Denigrating someone involves making derogatory remarks that can damage their reputation or undermine their standing. This word is often used in contexts where someone is attempting to diminish another's worth or credibility, either through criticism or slanderous comments.

In contrast, deprecate generally means to express disapproval of something or to diminish the value of something but does not inherently carry the connotation of attacking a person's character. Desiccate refers to drying out or the removal of moisture, which is unrelated to character attacks. Dichotomy denotes a division or contrast between two things that are represented as being opposed or entirely different, also not applicable to the context of speaking ill of someone.