Ad hominem (Latin for 'to the person'), short for argumentum ad hominem, refers to several types of arguments that are fallacious. Often nowadays this term refers to a rhetorical strategy where the speaker attacks the character, motive, or some other attribute of the person making an argument rather than the substance of the argument itself. This avoids genuine debate by creating a diversion often using a totally irrelevant, but often highly charged attribute of the opponent's character or background. The most common form of this fallacy is "A" makes a claim of "fact", to which "B" asserts that "A" has a personal trait, quality or physical attribute that is repugnant thereby going off-topic, and hence "B" concludes that "A" has their "fact" wrong – without ever addressing the point of the debate. Many contemporary politicians routinely use ad hominem attacks, some of which can be encapsulated to a derogatory nickname for a political opponent used instead of political argumentation. (But modern democracy requires that voters make character judgements of representatives, so opponents may reasonably criticize their character and motives.)
Other uses of the term ad hominem are more traditional, referring to arguments tailored to fit a particular audience, and may be encountered in specialized philosophical usage. These typically refer to the dialectical strategy of using the target's own beliefs and arguments against them, while not agreeing with the validity of those beliefs and arguments. Ad hominem arguments were first studied in ancient Greece; John Locke revived the examination of ad hominem arguments in the 17th century.
A common misconception is that an ad hominem attack is synonymous with an insult. This is not true, although some ad hominem arguments may be insulting by the person receiving the argument.