Someone that is overtly condescending and cocky about their abilities and firmly believes in their own perfection. If you aren't as good as them (and you're not) it's because you're stupid.
Others dream and reminisce of the inevitable times when the cocky paladin meets some thing or person that simply destroys him, hopefully in a very humiliating fashion and always because of their cockiness.
Used most often in reference to video gaming, but works for real world also. Cocky paladins that are also flash bastards are true hate magnets.
(When someone is being a dick)
Dude, don't be another cocky paladin.