Lack of knowledge.
- Excessive and/or forbidden knowledge. "Ignorant" refers not to someone who knows too little, but rather to someone who knows "too much": someone who is well-informed about taboo subjects such as conspiracy theories or alternative science; someone who possesses critical information exposing institutional lying and disinformation.
- Lack of faith. "Ignorant" is someone who refuses to believe to accepted dogma (in other words: a skeptic); in this sense, "ignorant" can be thought as the modern equivalent of "infidel".