An important and powerful person, especially in an organization
e.g Boss Duong played an important role in this conference, he’s a big cheese
Two people who are completely different from each other
e.g Though they’re twin sisters, they look really chalk and cheese
To have no sympathy for someone going through a hardship
e.g This is the only food we have left and if you don’t like it, hard cheese
More holes than swiss cheese
to be flawed or to be unsound