Meaning:

A person who behaves in a very formal way and is often self-important. A very conservative person.

If someone is a stuffed shirt , his/her behavior is very formal, and he/she thinks he/she is a very important person.

Example: He's such a stuffed shirt. He always instructs us how to use each knife and fork every time we go to dinner with him.

My boss is a true stuffed shirt. She's very formal and rigid all the time and not an interesting person to talk with.

Twitter