ignorant has 7 distinct synonyms spread across 3 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
uneducated in general; lacking knowledge or sophistication
“an ignorant man”
uneducated in the fundamentals of a given art or branch of learning; lacking knowledge of a specific field
“she is ignorant of quantum mechanics”
unaware because of a lack of relevant information or knowledge
“he was completely ignorant of the circumstances”
Synonyms, antonyms and the broader and narrower relations for ignorant come from Princeton University’s WordNet. Full sources and licences.