Definitions of whitewash:

• noun:   a specious or deceptive clearing that attempts to gloss over failings and defects
• noun:   wash consisting of lime and size in water; used for whitening walls and other surfaces
• noun:   a defeat in which the losing person or team fails to score
• verb:   cover up a misdemeanor, fault, or error

  Example: "Let's not whitewash the crimes of Stalin"

• verb:   exonerate by means of a perfunctory investigation or through biased presentation of data
• verb:   cover with whitewash

  Example: "Whitewash walls"