Ignorance and Stupidity are two words that go together, but they are not totally the same. Ignorance is simply a condition of being uneducated or informed about something. When you have not come or when you have not been exposed to the truth about a particular thing, that is when ignorance comes to showcase itself. In a simple term, ignorance means lack of information and awareness about a particular thing.
Stupidity, on the other hand, is the state or condition of not being able to understand something. This is where Stupidity is different from ignorance. Ignorance means you have not been exposed to information, but Stupidity means, even after you have been exposed to that information, you still found it difficult to comprehend accurately. In a simple term, Stupidity means lack of intelligence, which is mostly caused by mental deficiency. Most of the time, ignorance can lead to Stupidity.