Inconvincible
Pronunciation : In`con*vin"ci*ble
Part of Speech : a.
Etymology : [L. inconvincibilis. See In- not, and Convince.]
Definition : Defn: Not convincible; incapable of being convinced. None are so inconvincible as your half-witted people. Gov. of the Tongue.
Source : Webster's Unabridged Dictionary, 1913