dis·an·nul /ˌdɪsəˈnʌl/
  (vt.)取消,使無效
  Dis·an·nul v. t. 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.
  Note: ☞ The prefix in this word an its derivatives is intensive, and not negative.
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