Sound like a pig (4)
I believe the answer is:
oink
'sound like a pig' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for oink that I've seen before include "Sound from a sty" , "Piggish noise" , "What farmer hears" , "Noise a pig makes" , "Pig's grunt" .)