uneducated in the fundamentals of a given art or branch of learning; lacking knowledge of a specific field; "she is ignorant of quantum mechanics"; "he is musically illiterate"
uneducated in general; lacking knowledge or sophistication; "an ignorant man"; "nescient of contemporary literature"; "an unlearned group incapable of understanding complex issues"; "exhibiting contempt for his unlettered companions"
unaware because of a lack of relevant information or knowledge; "he was completely ignorant of the circumstances"; "an unknowledgeable assistant"; "his rudeness was unwitting"
the flash of light that accompanies an electric discharge in the atmosphere (or something resembling such a flash); can scintillate for a second or more
abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light