Argumentum ad hominem

noun (logic)
fallacious argument that attacks not an opponent’s beliefs but his motives or character
argument that shows an opponent’s statement to be inconsistent with his other beliefs
an instance of either of these
Historical Examples

You have nobly substituted the argumentum ab humanitate for the argumentum ad hominem, which you so justly condemn.
Charles Sumner; His Complete Works, Volume VIII (of 20) Charles Sumner

It was an argumentum ad hominem, and drawn from a popular faith.
Narrative And Miscellaneous Papers Thomas De Quincey

It was a masterful bit of hypocritical eloquence, of argumentum ad hominem; but it was made to simple and illiterate hearers.
The Code of the Mountains Charles Neville Buck

I have necessarily, in answering the Senator, gone somewhat into the argumentum ad hominem.
The Life of Jefferson Davis Frank H. Alfriend

It was not to this, however, that he directed his objection: the argumentum ad hominem came more easily to him.
The Long Night Stanley Weyman

The latter had nothing better to appeal to than that notoriously feeble resource, the argumentum ad hominem.
The Teaching of Epictetus Epictetus

The fallacy in logic known as the argumentum ad hominem becomes a pale thing in comparison with this new argumentum ad terram.
The Birth of Yugoslavia, Volume 1 Henry Baerlein

In a case like this the argumentum ad hominem, though a perfectly fair one, is a perfectly useless one.
The Contemporary Review, Volume 36, November 1879 Various

argumentum ad hominem—appealing to an opponent’s professed views.
A Logic Of Facts George Jacob Holyoake

This line of defence may, as against Home Rulers, be disposed of at once by an argumentum ad hominem.
A Leap in the Dark A.V. Dicey