the GNU version of the Collaborative International Dictionary of English
v. To annul completely; to render void or of no effect.
The Century Dictionary and Cyclopedia
To make void; annul; deprive of force or authority; cancel.
To deprive (of).
Word Usage
"Sometimes disingenuous is used as a synonym for naive, as if the dis - prefix functioned as an intensive (as it does in certain words like disannul) rather than as a negative element."