(obsolete) Any liquid composition for whitening something, such as a wash for making the skin fair.

Example: A lime and water mixture for painting walls and fences bright white.
1952, L. F. Salzman, Building in England, page 157:
  For walls plaster gave a smooth white surface; or if it was not sufficiently white, or had become discoloured, it could be brightened up with a coat of whitewash or paint.
2010, Andrew Miller, Cricinfo:
  For the first time in a long time, Australia are being threatened with the prospect of a 5-0 whitewash
  (Can we find and add a quotation of Addison to this entry?)