Sam’s out hiding the gold in the marsh (6)
I believe the answer is:
morass
'the marsh' is the definition.
(I've seen this in another clue)
'sam's out hiding the gold' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'hiding' indicates putting letters inside.
'the gold' becomes 'or' ('or' is the heraldic name for gold).
'sams' with letters rearranged gives 'mass'.
'mass' going around 'or' is 'MORASS'.
'in' is the link.
(Other definitions for morass that I've seen before include "Tract of swampy land" , "Tract of soft, wet ground" , "complicated situation" , "Muddled situation" , "Slough, bog" .)