Pop open (6)
I believe the answer is:
uncork
'pop open' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for uncork that I've seen before include "Clear a bottleneck" , "Release the stopper" , "Open (Chablis, say)" , "Remove traditional stopper from wine bottle" , "Open (a wine bottle)" .)