Oxford Dictionary
discoloured
discoloured |dɪsˈkʌləd |(US discolored ) ▶adjective changed in colour in a way that is less attractive: her beauty was marred by discoloured teeth.
Oxford Thesaurus
discoloured
discoloured adjective the shaft of the sword was twisted and discoloured: stained, marked, spotted, dirty, soiled, tarnished, blackened; bleached, faded, yellowed; rusted, rusty, oxidized, weathered. ANTONYMS shiny, clean.