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
Word Origin for argumentum ad hominem
literally: argument to the person
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012