confute \kuhn-FYOOT\ (transitive verb) - To overwhelm by argument; to refute conclusively; to prove or show to be false.
"And can there still be any need to confute the Diatribe? Who can more effectually confute it, than it confutes itself! This truly, is that beast that devours itself! How true is the proverb, that 'A liar should have a good memory!'" -- Martin Luther, 'The Bondage of the Will'
Confute is from Latin confutare, "to check the boiling of a liquid; to put down; to silence."