漆喰は粉飾の材料！？ ― whitewash

水漆喰（しっくい）というのが原義で、実際その意味で使われることもあるようですが、日本語でも聞きなれない言葉です。要は、壁を白くするするのに用いるということで、“白”のイメージはすなわち、“潔白”ですから、


うわべを繕う、粉飾する、歪曲する


といったややネガティヴな意味に発展したようです。

名詞としても、取り繕い、粉飾、という意味で用いられます。

Relatives of victims said they pressed for an independent inquiry and expressed fear that the panel's report would be a whitewash that shifted the responsibility from managers to the victims. "The dead can not defend themselves, and so they are the easiest to blame for this catastrophe," said Mr. Almeida, who accused the air force of withholding vital information. "There are too many interests at stake for the truth to be told, especially by a commission like this one."
(New York Times. 2004)


下記は動詞の例です。

Talk, talk, talk. Express your feelings to your mate. Good communication is a boost to any relationship, and those couples with the most loving and harmonious relationships seem to have no problem talking to each other about anything and everything. Don't whitewash your marital problems and let them simmer. If there are conflicts, talk them out with your mate. Dr. Bennett suggests that couples also should "stimulate" each other's minds. "Read and share ideas," she says.
(Lynn Norment. 10 secrets to a happy marriage. Ebony. 1993.)