Ignorance is the state of simply not having had access (or interest to seek out access) to certain information. It says nothing about the competency of the person who is ignorant. For example, I am almost wholly ignorant of how a car engine works, though I could bore you for hours on the history of film editing.
Stupidity, on the other hand, is knowing you are ignorant and refusing to educate yourself. It could also be described as being willfully ignorant. Stupidity is also very well defined by knowing the information and choosing to ignore it. Or, as they say, “Doing the wrong thing over and over and expecting different results.”
I’m watching the Albert Nerenberg documentary Stupidity (2003) (which includes such luminaries as John Cleese, Bill Maher and Noam Chomsky) and one of the questions they initially ask of people is, “What is stupidity?” which got me thinking and, after some consideration, the above definitions are my opinion.
What do you think stupidity is?
On The Other Hand 
“(or interest to seek out access)”
Isn’t not being interested in seeking information the same thing as being aware of it and remaining inactive?
On the whole, I agree. I’ve watched people make entire conversations without exchanging or evaluating anything.
A point of interest: This train of thought assumes that the only happy state for humans is one of nearly constant intellectual growth. Is it possible for someone to reach a point at which they no longer thirst for knowledge? If a wise person makes a conscious effort to stop learning in all its forms, can they be content, and if so, are they now stupid?
I don’t know, Dan. Have you reached that point? Do you know anybody you respect who has decided they know everything there is to know about the world?
In my opinion, knowing that a deeper knowledge exists and not seeking it IS a crime against yourself, so remaining inactive is an act of stupidity.
Haha, in no way have I even come close to knowing all I want.
Would excellence and perfection of a craft be considered knowledge?
Excellence in craft is absolutely knowledge! I’m not sure how it could not be considered knowledge… I don’t think I’ll ever know everything I want to, and I bet you never will either, Dan =)