The compound adjective 'white-robed' is a transparent descriptive formation in English. Its first element, 'white', descends from the Proto-Germanic hwītaz, a word of ancient lineage ultimately from the Proto-Indo-European root ḱweyt- meaning 'to shine; bright'. The second element originates from the Old French robe, meaning 'garment' or 'booty', which itself came from a West Germanic source related to 'rob', reflecting the original sense of seized plunder, which often included clothing. The combination follows a common English pattern (e.g., 'long-haired', 'blue-eyed') where an adjective is attached to a noun with the -ed suffix to denote possession of that quality, literally meaning 'having the characteristic of wearing a white robe'.

Structure: white (color) + robed (clothed) - white: From Old English hwīt, of Germanic origin; related to Dutch wit and German weiss. Functions as an adjective describing color. - robed: From the verb robe, from Old French, of Germanic origin; related to the noun robe. The suffix -ed is added to form a participial adjective meaning 'wearing' or 'clothed in'.