A person who cares only for himself and thinks he is better than anyone else. He believes no one except him has feelings and yet is still liked by many people. Girls like him but would be stupid to get involved with him.
See that guy with his head up his backside?
Hes such a perlmutter
someone who is really smart, but will not let anyone cheat off of them
Jon: Yo, iv'e been Dan's friend for years, and this morning i asked if i could copy his math homework so i wouldn't get a zero, and he said no.
Peter: yea, Dan can be a real perlmutter sometines.