Cancels (6)
I believe the answer is:
annuls
'cancels' is the definition.
(annulling is a kind of canceling)
This is the entire clue.
(Other definitions for annuls that I've seen before include "Renders boid" , "Cancels, makes void" , "Cancels, abolishes" , "Cancels officially" , "Repeals or rescinds" .)