Tarnish :  (noun)

1: discoloration of metal surface caused by oxidation (verb)

1: make dirty or spotty, as by exposure to air; also used metaphorically; "The silver was tarnished by the long exposure to the air"; "Her reputation was sullied after the affair with a married man" [syn: stain, maculate, sully, defile]

achromatize, asperse, aspersion, attaint, badge of infamy, bar sinister, baton, bedaub, befoul, begrime, benasty, bend sinister, besmear, besmirch, besmoke, besoil, bespatter, bestain, black eye, black mark, blacken, blanch, bleach, blemish, bloodstain, blot, blotch, blow upon, blur, brand, broad arrow, call names, calumniate, censure, champain, contaminate, corrupt, dab, damage, darken, daub, debase, decolor, decolorize, defame, defile, degrade, denigrate, dim, dirty, disapprove, discolor, disgrace, dishonor, disparage, disparagement, drain, drain of color, dull, embarrass, engage in personalities, etiolate, expose, expose to infamy, eyesore, fade, fleck, flick, flyspeck, foul, fume, gibbet, grime, hang in effigy, harm, heap dirt upon, hurt, impair, imputation, infect, injure, macula, maculation, macule, mar, mark, mark of Cain, mess, mess up, muckrake, muddy, nasty, onus, pale, patch, peroxide, pillory, pillorying, point champain, pollute, prejudice, reflection, reprimand, reproach, revile, ruin, scorch, sear, singe, slander, slubber, slur, smear, smirch, smoke, smooch, smouch, smudge, smut, smutch, soil, spatter, speck, speckle, splash, splatter, splotch, spoil, spot, stain, stigma, stigmatism, stigmatization, stigmatize, sully, taint, tar, throw mud at, tone down, vilify, vitiate, wash out, whiten,