The compound "wide-awake" is a native English formation, combining two Old English elements to create a vivid metaphorical expression. The adjective "wide," originally denoting physical breadth, was used figuratively from Middle English onward as an intensifier, akin to "fully" or "broadly." Paired with "awake," which stems from the Old English verb for rousing from sleep, the term literally means "fully roused." This literal sense of being completely alert evolved naturally into its modern figurative meanings, describing not just a state free from drowsiness but also sharp mental awareness and keen perception of one's surroundings or circumstances.

Structure: wide (broad, fully) + awake (not sleeping) - wide: From Old English wīd (spacious, extensive). In this compound, it functions as an intensifier meaning "fully" or "completely". - awake: From Old English āwæcnan (to arise, to wake up). It is the adjective form meaning "not asleep; alert".