n discoloration of metal surface caused by oxidationv make dirty or spotty, as by exposure to air; also used metaphorically
n. 污点, 瑕疵, 无光泽( tarnish的名词复数 )v. （通常指金属）（使）失去光泽, （使）变灰暗( tarnish的第三人称单数 ); 玷污, 败坏