If you describe someone as ignorant, you mean that they do not know things they should know. If someone is ignorant of a fact, they do not know it.
People don't like to ask questions for fear of appearing ignorant.
人们不喜欢问问题,生怕显得自己无知。
People are sometimes described as ignorant when they do something that is not polite or kind.
I met some ignorant people who called me all kinds of names.
我遇到了一些粗鲁的人,他们用各种脏话辱骂我。