Big Cheese original pen and ink and watercolour illustration by Rosie Brooks

The phrase "big cheese" is an idiomatic expression that refers to an important or influential person, often someone in a position of authority or power. It is typically used in a colloquial or informal context.

The origin of the phrase is uncertain, but it is thought to have emerged in the early 20th century. The term "cheese" may have been used metaphorically to represent something of high value or quality, and when combined with "big," it emphasizes the significance or prominence of the person being referred to.

Here are a few examples of how the phrase "big cheese" might be used:

1. "John is the big cheese at the company; he's the one who makes all the major decisions."
2. "Sheila is the big cheese in the music industry; her influence can make or break a career."
3. "The CEO is the big cheese around here; everyone looks up to him for guidance and leadership."

Overall, "big cheese" is a colloquial expression that portrays someone as an important figure, often with a sense of respect or authority.