Tarnish is defined as to spoil or to discolor the surface of a piece of metal.(verb)
An example of to tarnish is to expose silver to sulfur and air.
See tarnish in Webster's New World College Dictionary
Origin: < Fr terniss-, inflectional stem of ternir, to make dim < MFr, prob. < OHG tarnjan, to conceal < tarni, hidden
See tarnish in American Heritage Dictionary 4
verb tar·nished, tar·nish·ing, tar·nish·es verb, transitive
Origin: Middle English ternisshen
Origin: , from Old French ternir, terniss-, to dull
Origin: , from terne, dull
Origin: , of Germanic origin.
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