WHITEWASH

a solution of lime and water or of whiting, size, and water, used for painting walls white.

a deliberate attempt to conceal unpleasant or incriminating facts about a person or organization in order to protect their reputation

a victory by the same side in every game of a series

paint (a wall, building, or room) with whitewash

deliberately attempt to conceal unpleasant or incriminating facts about (someone or something)

defeat (an opponent) in every game of a series