Entry 2 senses Webster, 1913 Unquestionable /ən-kwĕs'-chən-əb-əl/ · Un·ques·tion·a·ble · IPA /ʌnˈkwɛs.t͡ʃən.ə.bl̩/ 01 a. Not questionable; as, an unquestionable title. 1. Not questionable; as, an unquestionable title. 2. Not inviting questions or conversation.[R.]