Question: What is ignorance in Islam?

Answer: Ignorance of God 

Question: What is jahl and who is the Jāhil?

Answer: Jahl is foolishness when it comes to truth. The jāhil is the fool. 

Question: Can a jāhil have knowledge?

Answer: Yes, he can have a lot of information, but still be a fool, like the Devil. 

Question: What are other words similar to jahl in Islam?

Answer: Safaahah is one, which means foolishness or idiocy.   

Question: What is wisdom in Islam?

Answer: Wisdom is to be able to put knowledge to relevant use to the benefit of the greater good.