Does anybody know what the root word of ignorance

Does anybody know what the root word of ignorance is? It seems that when someone doesn't agree or like what you say the put you on ''ignore''. Are those the same type that believe the world is flat? Remember when suggesting the world was round and you were considered a heretic/basher. Aristotle...basher or whistleblower? I'll never know because I choose to ignore. Bored.