ammunition has 1 distinct synonym spread across 1 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.
any nuclear or chemical or biological material that can be used as a weapon of mass destruction
information that can be used to attack or defend a claim or argument or viewpoint
“his admission provided ammunition for his critics”
Synonyms, antonyms and the broader and narrower relations for ammunition come from Princeton University’s WordNet. Full sources and licences.