Probably generated ability scores by dice or some other random way and ended up with a bunch of random ability scores. His level 4 ability score could have been spent in Strength bringing it to 12 or 14 or something...
Invest in Intelligence. Put some ranks in knowledge skills and unless there's a knowledge focused wizard nearby you can be arrogant just by knowing it all and better than the others.
Paladin: 'Oh that's because it functions this and that way.'
Duelist: *with haughty voice* Actually it only seems to work this way, it works (enter complex description here) and you mr. paladin are plain stupid.
Note that you can be very haughty by always correcting others and adding that they are stupid. Even if someone wants to compare some things with you where they are actually better than your duelist, just tell them that this is irrelevant and that they are stupid to rely/focus on such a useless thing.
I bet you can bring the other players to actually kick you out of the party with that behaviour.