Blackwashing is a term for casting a Black actor for a character that is in real history or in the original fictional story not Black.
"Whitewashing" is a term for when an analogous casing occur in favor of Whites. Today, Blacks characters are very rarely played by White actors, and if they do, this is often strongly protested, unlike when White characters are played by Blacks, one of many politically correct double standards. When Whitewashing occur today, this mostly involves instances such as characters of (partly) Asian or Amerindian ancestry being played by Whites, and even this occur rarely. Anti-White Wikipedia has an article on Whitewashing, but not on Blackwashing.