Bar excluding others? Not entirely! (5)
I believe the answer is:
ingot
'bar' is the definition.
(block of metal, eg a bar of gold)
'excluding others? not entirely' is the wordplay.
'not entirely' indicates the answer is hidden within the clue.
'INGOT' can be found hidden inside 'excluding others'.
(Other definitions for ingot that I've seen before include "A lump of metal, perhaps gold" , "Cast metal brick" , "Lump of gold etc" , "Mass of precious metal" , "Brick-shaped lump of cast metal" .)