Trickle (through) (4)
I believe the answer is:
seep
'trickle through' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for seep that I've seen before include "Come out slowly" , "Trickle through slowly" , "Leak gradually" , "Ooze, percolate" , "Leak slowly, ooze" .)