Intelligent people have the sense not to be arrogant.
Intellegent people know that what they know is nothing compared to what they have to learn.
Intelligent people don't presume to be more intelligent than others.
Intelligent people strive to better themselves not so they can say "I'm really smart me" but so they can think "I am stretching my own capabilities and gaining a better understanding of the world".

IMO stupid is more about how you are than what you know, the "smartest" intellectual can be just as stupid as the so called idiot.

I have a friend who is "educated" and has more diplomas than you can shake a stick at but he does some really stupid things and then I have another friend who is "dumb" (bad schooling) and if I ever need my own McGyver this man rules, he can make anything out of nothing.

So in conclusion would someone please like to give me a suitable definition of "Intelligent" because you can be book smart but you also need a bit of street smarts if you want to make it in this life.