ic has 5 distinct synonyms spread across 2 of its 2 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.
a group of government agencies and organizations that carry out intelligence activities for the United States government; headed by the Director of Central Intelligence
being one less than one hundred and nine more than ninety
Synonyms, antonyms and the broader and narrower relations for ic come from Princeton University’s WordNet. Full sources and licences.