Sound like a pig in fine surroundings (4)
I believe the answer is:
oink
'sound' is the definition.
(I have seen 'Sound of pig' mean 'oink' so perhaps 'sound' could also mean 'oink')
'in fine surroundings' is the wordplay.
'fine' becomes 'ok' (synonyms).
'surroundings' means one lot of letters goes inside another.
'in' going inside 'ok' is 'OINK'.
'like a pig' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for oink that I've seen before include "Swine sound" , "Animal sound" , "farmyard noise" , "it might be in a pen one hears" , "Piggish noise" .)