savings bank has 3 distinct synonyms spread across 1 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 thrift institution in the northeastern United States; since deregulation in the 1980s they offer services competitive with many commercial banks
a container (usually with a slot in the top) for keeping money at home
“the coin bank was empty”
Synonyms, antonyms and the broader and narrower relations for savings bank come from Princeton University’s WordNet. Full sources and licences.