Sam

Sam means "a smart person, being good at everything related to school". It means "a nerd". Being a Sam means "being a nerd".

He must be Sam, because he has round glasses and he is always in the library. (He must be a nerd, because he has round glasses and he is alsways in the library.)
You're being a Sam! (You're being a nerd!)
I'm not a Sam! (I'm not a nerd!)