Disproven is the past participle of disprove, from dis- ('reversal') + prove, from Latin probare ('to test, prove'), from probus ('good, upright'). The ancestry passes through Latin probare and Latin probus. The prefix dis- often marks separation, reversal, or negation in Latin and English formations, helping to explain the word's surface structure. In present use as adjective and verb, it means "shown to be false or invalid", keeping the historical formation close to the word's ordinary semantic work. Related words include disprove, prove, proven, and disproof.