What is "ad hominem" reasoning?

Ad hominem reasoning refers to a logical fallacy where an argument is rebutted by attacking the character or motive of the person making the argument, rather than addressing the substance of the argument itself. This type of reasoning diverts attention away from the actual issue and instead focuses on discrediting the individual, which does not contribute to a rational evaluation of the argument at hand.

In the context of the other options, using logical comparisons between scenarios pertains to analogical reasoning, which is not related to personal attacks. Presenting data to support an emotional claim involves a different kind of reasoning altogether, focusing on appeals to emotion rather than character. Lastly, defining terms within an argument relates to clarifying the language used rather than criticizing the individual presenting the argument. These alternatives do not capture the essence of ad hominem reasoning, which is specifically about the individual making the argument, making the second choice the most accurate definition.