discoloration of metal surface caused by oxidation
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"
in or to a backstage area of a theater; "costumes were changed backstage"
out of view of the public; behind the scenes; "Working backstage to gain political support for his proposal"; "many private deals were made backstage at the convention"