Big cheese

This expression refers to the most influential person, the boss, the person in authority. Depending on the context, it may or may not be disrespectful or derogatory. It appears to stem from the only positive slang meaning of ‘the cheese’ which, from the early 19th century, meant the best, the in-fashion or the correct thing. Some sources ascribe this to the Hindi or Urdu word chiz, pronounced cheese meaning the thing as in the real thing but this is not proven. See also cheese, cheesed off, cheesy and hard cheese.