Entry 1 sense Webster, 1913 Disannul · Dis·an·nul · IPA /dɪsəˈnʌl/ 01 v. t. To annul completely; to render void or of no effect. 1. To annul completely; to render void or of no effect. “For the Lord of hosts hath purposed, and who shall disannul it?” — Isaiah xiv. 27.