tarnish |ˈtärniSH|
verb
lose or cause to lose luster, esp. as a result of exposure to air or moisture: [ no obj. ] : silver tarnishes too easily | [ with obj. ] : lemon juice would tarnish the gilded metal.
• make or become less valuable or respected: [ with obj. ] : his regime had not been tarnished by human rights abuses.
noun
dullness of color; loss of brightness.
• a film or stain formed on an exposed surface of a mineral or metal.
• damage or harm done to something.
DERIVATIVES
tarnishable adjective
ORIGIN late Middle English (as a verb): from French terniss-, lengthened stem of ternir, from terne ‘dark, dull.’