Not watertight (5)
I believe the answer is:
leaky
'not watertight' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for leaky that I've seen before include "Not watertight" , "Letting gas/liquid out" , "Divulging secrets" , "Perforated" , "Unable to keep secrets" .)