The Collaborative International Dictionary
Ad hominem \Ad hom"i*nem\ [L., to the man.] A phrase applied to an appeal or argument addressed to the principles, interests, or passions of a man.
Douglas Harper's Etymology Dictionary
c.1600, Latin, literally "to a man," from ad "to" (see ad-) + hominem, accusative of homo "man" (see homunculus).
Wiktionary
a. Of or relating to ad hominem. adv. In an ad hominem manner. n. 1 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 himself. 2 A personal attack.
WordNet
adj. appealing to personal considerations (rather than to fact or reason); "ad hominem arguments"
Wikipedia
Ad hominem ( Latin for "to the man" or "to the person"), short for argumentum ad hominem, is a logical fallacy in which an argument is rebutted by attacking the character, motive, or other attribute of the person making the argument, or persons associated with the argument, rather than attacking the substance of the argument itself.
Ad hominem reasoning is not always fallacious, for example, when it relates to the credibility of statements of fact or when used in certain kinds of moral and practical reasoning.
Fallacious ad hominem reasoning is normally categorized as an informal fallacy, more precisely as a genetic fallacy, a subcategory of fallacies of irrelevance.
Usage examples of "ad hominem".
Since ad hominem seems to be the mode of argument here, my own observation is that these particular critics seem to gravitate to the past phylogenetic structure that corresponds with the ontogenetic structure in themselves that is immediately prior to their failed personal integration.
And your response was first to ignore it, and then to make an ad hominem attack.
The ad hominem fallacy consists of attempting to refute an argument by impeaching the character of its proponent.
When they are asked to produce it or cite some reference, the usual response is ridicule or some ad hominem attack imputing motives.