Cancel regular publication when article is omitted (5)
I believe the answer is:
annul
'cancel' is the definition.
(I know that annul is a more specific form of the action cancel)
'regular publication when article is omitted' is the wordplay.
I cannot really understand how this works, but
'article' could be 'an' (English indefinite article) and 'an' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for annul that I've seen before include "scratch" , "Countermand" , "Render invalid" , "Nullify" , "Make invalid" .)