The compound adjective "well-supported" is a modern English formation built from native Germanic and Latinate elements. The adverb "well," with ancient Germanic roots related to welfare and desire, intensifies the past participle of "support," a verb descended from Latin meaning "to carry from below." The literal image is of something being thoroughly upheld or borne. Over time, this concrete sense broadened into the modern abstract meanings, where an argument is figuratively upheld by evidence, or a project is sustained by ample resources, both conveying a state of being firmly and satisfactorily maintained.

Structure: well (in a good manner) + support (hold up) + ed (adjective suffix) - well: From Old English wel, meaning "in a good manner, satisfactorily." It functions as an intensifying adverb modifying the participle. - support: From Latin supportare (sub- "from below" + portare "to carry"). It functions as the verbal root meaning "to bear, uphold, sustain." - ed: From Old English -ed, -od, -ad, a suffix forming the past participle of verbs, here used to create a participial adjective.