Wild pig hides in cupboard (4)
I believe the answer is:
boar
'wild pig' is the definition.
(I've seen this before)
'hides in cupboard' is the wordplay.
'hides in' says the answer is hidden in the clue (I've seen 'hidden in' mean this).
'BOAR' can be found hidden inside 'cupboard'.
(Other definitions for boar that I've seen before include "Wild pig sounds tedious" , "A male pig, sounds tedious" , "Sow's mate" , "Male swine" , "A wild male pig" .)