Fish found in buffet car, perhaps (4)
I believe the answer is:
carp
'fish found in buffet' is the definition.
'carp' can be an answer for 'fish' (I've seen this before). I am not sure about the 'found in buffet' bit.
'car perhaps' is the wordplay.
'perhaps' becomes 'p' (this could be a standard abbreviation which I don't know about).
'car'+'p'='CARP'
Can you help me to learn more?
(Other definitions for carp that I've seen before include "Fish - complaint" , "Moan; fish" , "Complain continually" , "Fish - make captious criticism" , "praise? The opposite" .)