tarnished  
adjective uk/ˈtɑː.nɪʃt/ us/ˈtɑːr.nɪʃt/
  (METAL)      
  (金属)失去光泽的,变色的
If metal is tarnished it has become less bright or a different colour.
  The photographs were in tarnished silver frames. 这些照片装在褪色的银色相框里。 
 - More examples
 - People trade in their tarnished gold chains, old wedding bands or gold-filled teeth.
 - She had rinsed out the tub, and lowered the big and tarnished metal plug into the hole.
 - Medallions were tarnished and corroded.
 
  (LESS GOOD)      
 受诽谤的;被中伤的
made to seem less good or respected
  By 2015, the company was starting to look a little tarnished. 到2015年,该公司开始显得有些黯然失色。 
 See: tarnish
 - More examples
 - To those of us who truly know him, his good name could never be tarnished.
 - a celebrity with a more tarnished image
 - He has only himself to blame for his tarnished legacy.
 - He is desperate to salvage something that would burnish his very tarnished leadership credentials.