Cancels yearbooks after the fifth fails to show (6)
I believe the answer is:
annuls
'cancels' is the definition.
(annulling is a kind of cancelling)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for annuls that I've seen before include "Renders boid" , "Cancels, makes void" , "Repeals or rescinds" , "Declares invalid" , "Cancels officially" .)