big cheese

Example: “The big cheese from headquarters is visiting our office tomorrow.”

Origin: Grew out of the earlier American "main cheese," an important or self-important person, recorded from 1899; "big cheese" itself is on record by 1922, in the Olean Evening Times. Two explanations compete for why cheese specifically. One reaches for British colonial India, where English speakers are supposed to have picked up the Urdu chiz, meaning "thing," and mangled "the real chiz" — something genuinely impressive — into "the real cheese" and eventually "the big cheese." The other points to something far more literal and American: enormous ceremonial cheeses, sometimes weighing thousands of pounds, built and put on public display in the early 20th century as promotional stunts, giving "big cheese" an image that needed no borrowed language to explain it.