The compound adjective 'sun-warmed' is a transparent and relatively modern English formation. Its first element, 'sun', descends from the Proto-Germanic sunnōn, a feminine noun whose Proto-Indo-European ancestor is thought to be sóh₂wl̥, meaning 'the sun'. The second element, 'warm', originates from Proto-Germanic warmaz, itself from the PIE root gʷʰer-, meaning 'warm, hot'. The suffix '-ed' is the productive participial ending. The word's logic is perfectly literal, directly describing the state of being heated by solar radiation, a concept that has been expressible since the Old English period by simply combining the extant words for 'sun' and 'warm'.

Structure: sun (star) + warm (heat) + ed (adjective suffix) - sun: From Old English sunne, of Germanic origin; related to Dutch zon and German Sonne. Functions as a noun root specifying the source of warmth. - warm: From Old English wearm, of Germanic origin; related to Dutch and German warm. Functions as an adjective root denoting the state of moderate heat. - ed: A past participle suffix from Old English -ed, -od, -ad, used here to form a participial adjective indicating a state resulting from an action.