1.Definition: unaware because of a lack of relevant information or knowledge

"He was completely ignorant of the circumstances"

Related Adjective(s):unknowing, unknowledgeable, unwitting

2.Definition: uneducated in general; lacking knowledge or sophistication

"An ignorant man"

Related Adjective(s):nescient, unlearned, unlettered

3.Definition: uneducated in the fundamentals of a given art or branch of learning; lacking knowledge of a specific field

"She is ignorant of quantum mechanics"

Related Adjective(s):illiterate