transitive verb.
To free from a falsehood or misconception.
The Century Dictionary and Cyclopedia
To free from mistake; undeceive; relieve from fallacy or deception; set right: as, it is our duty to disabuse ourselves of false notions and prejudices.
the GNU version of the Collaborative International Dictionary of English
transitive verb.
To set free from mistakes; to undeceive; to disengage from fallacy or deception; to set right; -- often used with of.