the word 'whiten' is a classic example of a denominal verb formed within the english language itself. its core, 'white', originates from the proto-germanic 'hwītaz', a term describing brightness and lightness, which itself derives from the proto-indo-european root 'kweyt-', meaning 'to shine' or 'be bright'. the addition of the old english verbal suffix '-en' (from '-nian') directly applies the action of 'making or becoming' to the quality of the root. thus, the literal construction 'to make white' has remained perfectly transparent and logical from its old english formation to its modern abstract meaning of causing a color change towards paleness.

Structure: white (color) + en (verb-forming suffix) white (from old english 'hwīt', meaning the color white; adjective root). en (from old english '-nian', a verb-forming suffix meaning 'to make or become').