'whitewash' originates from English, specifically a compound of 'white' + 'wash', where 'white' meant 'pale/bright' and 'wash' meant 'to wash or coat'.

'whitewash' developed in Middle English as a compound of Old English elements 'hwīt' (white) and 'wæscan' (to wash). It originally referred to a lime- or chalk-based coating used to whiten walls and other surfaces and later became a verb meaning 'to coat with whitewash' and, figuratively, 'to conceal faults'.

Initially, it meant 'a white coating applied to surfaces' (literal); over time it acquired the additional figurative meaning 'to conceal or gloss over wrongdoing or faults'.