Leak (through) (4)
I believe the answer is:
seep
'leak through' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for seep that I've seen before include "Come out slowly" , "Of liquid, ooze slowly out" , "Leak slowly, ooze" , "Trickle through slowly" , "Flow or leak slowly" .)