vital: [14] Vital comes via Old French vital from Latin vītālis. This was a derivative of vīta ‘life’. And vīta went back ultimately to Latin vīvus ‘living’, source of English vivacious, vivid, etc. Viable [19] is also descended from vīta, and etymologically means ‘capable of life’. => viable, vitamin, vivid[vital etymology, vital origin, 英语词源]