tarnisher
/ˈtɑrnɪʃər/Definitions
1. noun
A person or thing that tarnishes, especially something that causes moral or social deterioration
“The corrupt politician was seen as a tarnisher of the nation’s values.”
2. verb
To cause something to become discolored or lose its original shine, or to cause moral or social deterioration
“The years of neglect have tarnished the once-grand mansion.”