[ip-se dik-sit; English ip-see dik-sit]
an assertion without proof.
Origin of ipse dixit
< Latin: he himself said it
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
an arbitrary and unsupported assertion
Word Origin for ipse dixit
C16, literally: he himself said it
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
Latin, literally "he (the master) said it," translation of Greek autos epha, phrase used by disciples of Pythagoras when quoting their master.
Online Etymology Dictionary, © 2010 Douglas Harper