all-business

The compound adjective "all-business" is a modern American English formation, emerging in the 20th century to describe an intense, professional demeanor. It combines the universal intensifier "all," from the Old English eall, with "business," a word whose journey began with the Old English bisig (busy) and evolved to signify serious, profit-driven activity. The logic is transparently metaphorical: applying the totality of "all" to the domain of "business" creates an image of a person or attitude wholly consumed by purposeful, task-oriented seriousness, leaving no room for leisure or distraction. This construction follows a productive English pattern of using "all-" as a prefix to form adjectives denoting an exclusive quality, such as "all-knowing" or "all-powerful."

Structure: all (entirely) + business (commercial activity) - all: Old English origin, meaning "entire, whole, every." In this compound, it functions as an intensifier meaning "completely" or "solely." - business: Old English origin (from bisig "busy" + -ness), meaning "state of being busy; occupation; commercial enterprise." In this compound, it retains its core sense of serious, purposeful activity.