The term 'whitewash' originated in the late 16th century as a compound of the Old English words for the color 'white' and the action 'to wash'. Its literal sense refers to the inexpensive, brightening lime mixture applied to surfaces. The metaphorical sense, meaning to gloss over or conceal faults, emerged in the 18th century, drawing a direct analogy to the way a coat of whitewash can cover stains and imperfections, presenting a clean but superficial appearance. This semantic evolution perfectly captures the concept of making something superficially acceptable without addressing its underlying flaws.

Structure: white + wash + ed - white: From Old English 'hwīt', meaning the color white. In this compound, it denotes the color of the substance applied. - wash: From Old English 'wæscan', meaning to cleanse with water. In this compound, it denotes the action of applying a liquid coating. - ed: A suffix from Old English '-ed', '-od', '-ad', used to form the past tense and past participle of regular verbs, and subsequently adjectives from them.