It won't hold water (5)
I believe the answer is:
sieve
'it won't hold water' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sieve that I've seen before include "Jumblies' vessel" , "Screen, sift, strain" , "Utensil with meshed bottom" , "Wire mesh utensil" , "Mesh used for straining or sifting" .)