What is the difference between stupidity and ignorance?

Stupidity is when u are unintelligent, while with ignorance u may of may not be very smart but u just aren't very good at using your knowledge correctly.

Ignorance: when u simply don't know something, but u probably could learn it. A new person in train for example.

Stupidity: when u don't know something and probably can't learn it.

Ignorance is lack of knowledge.
Stupidity is lack of intelligence of common sense.
An intelligent person can be ignorant, and a stupid person can be knowledgeable.

stupidity means u have some knowledge but not a lot. Kinda like Dumb. But u can be Albert Einstein and not use your knowledge correctly of with any sense. that is being ignorant. :)