Leaky faucet sound (4)
I believe the answer is:
drip
'leaky faucet sound' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for drip that I've seen before include "Sissy" , "See 6" , "Fall in drops - weedy bloke" , "Fall or let fall in drops" , "Leak from tap" .)