treasury has 6 distinct synonyms spread across 4 of its 6 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.
the government department responsible for collecting and managing and spending public revenues
negotiable debt obligations of the United States government which guarantees that interest and principal payments will be paid on time
the British cabinet minister responsible for economic strategy
the federal department that collects revenue and administers federal finances; the Treasury Department was created in 1789
a depository (a room or building) where wealth and precious objects can be kept safely
Synonyms, antonyms and the broader and narrower relations for treasury come from Princeton University’s WordNet. Full sources and licences.