tarnish
noun/ˈtɑːnɪʃ/
/ˈtɑːrnɪʃ/
[singular, uncountable]- a thin layer on the surface of a metal that makes it look darker and less brightWord Originlate Middle English (as a verb): from French terniss-, lengthened stem of ternir, from terne ‘dark, dull’.
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