A stuck up can mean a tight fisted git who wouldn't want to spend money on their friends.
It can also mean that they only love themselves and they wouldn't care about anyone elses problems.
A stuck up is commonly known as a snob. Someone who's rich and would look down at you like you're not worth a penny.
Stuck ups think they can treat you how they like just because they might have some sort of high status.
They think they are someone special and think that they can run you down by calling you either childish or pathetic. They like to argue a bit like a chav
They pretend to care about a person when they really don't and are always acting stupid.