Crossword Genius

Cancel the Open (4)

Ross

I believe the answer is:

undo

I believe this is a double definition.

'cancel' is the first definition.
(thesaurus)

'the open' is the second definition.
(thesaurus)

(Other definitions for undo that I've seen before include "Release fastening" , "Bring to nought" , "Ruin or loose" , "Cause to become loose" , "Unfasten - destroy" .)

I've seen this clue in The Telegraph.
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