1.NounEllipsis of argumentum ad hominem: A fallacious objection to an argument or factual claim by appealing to a characteristic or belief of the person making the argument or claim, rather than by addressing the substance of the argument or producing evidence against the claim; an attempt to argue against an opponent's idea by discrediting the opponent themselves.
2.NounA personal attack.
"(Can we add an example for this sense?)"
3.AdjectiveOf or relating to this kind of fallacious objection.
"Well that's an ad hominem argument."
4.AdverbIn an ad hominem manner.
"He tried to make his case by arguing ad hominem."