The compound adjective "well-studied" is a transparent formation from native English elements. The adverb "well," with ancient Germanic roots related to wellness and goodness, is used as an intensifier to signify a high degree or thoroughness. It is combined with the participial adjective "studied," which derives from the Latin studium, conveying the sense of diligent application. The literal combination, "thoroughly examined," directly reflects the modern abstract meaning, describing a subject, phenomenon, or text that has been the object of extensive and careful academic or scientific investigation.

Structure: well (to a good or thorough degree) + studied (having been examined) - well: From Old English wel, meaning "in a good way, satisfactorily, thoroughly." It functions as an intensifying adverb in compound adjectives. - studied: From the past participle of the verb study, originating from Latin studium meaning "zeal, application." In this compound, it functions as an adjective meaning "having been the subject of study."