irrebuttable

[ ir-i-buht-uh-buh l ]
/ ˌɪr ɪˈbʌt ə bəl /

adjective

incapable of being rebutted or refuted.

Origin of irrebuttable

First recorded in 1825–35; ir-2 + rebuttable
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019