Metal bar obscuring other exhibits (5)
I believe the answer is:
ingot
'metal bar' is the definition.
('ingot' can be a synonym of 'metal bar')
'obscuring other exhibits' is the wordplay.
'exhibits' indicates a hidden word.
'INGOT' can be found hidden inside 'obscuring other'.
(Other definitions for ingot that I've seen before include "A lump of metal like gold" , "Precious metal bar" , "Piece of cast metal" , "Gold Stick" , "Block of cast metal" .)