Whitewash
To whitewash something is to paint it using whitewash. Whitewash is a white fluid which is used as an inexpensive and quick way to coat walls, fences, and other structures.It can be composed of different things. Generally, it is a mixture of slaked lime (Ca(OH)2), flour, salt, glue, and whiting. Sometimes molasses, water glass, or soap is added.
It is usually used externally, for example, to whitewash a fence, as Tom Sawyer was made to do. Occasionally, it is colored and used on interiors, such as in the hallways of apartment buildings.
The word "whitewash" is sometimes used (particularly in politics) to describe a cover-up or a deliberate downplaying of a problem.