Big gun and Superstar

Big gun noun - One of high position or importance within a group.

Superstar and big gun are semantically related in famous topic. In some cases you can use "Superstar" instead the phrase "Big gun" as a noun or an adjective, when it comes to topics like dignitary.

Superstar noun - A person who is widely known and usually much talked about.

Big gun and superstar are semantically related in dignitary topic. Sometimes you can use "Big gun" instead the word "Superstar" as a noun or an adjective.