currency has 2 distinct synonyms 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.
the metal or paper medium of exchange that is presently used
Synonyms, antonyms and the broader and narrower relations for currency come from Princeton University’s WordNet. Full sources and licences.
general acceptance or use
“the currency of ideas”
the property of belonging to the present time
“the currency of a slang term”