1. Something put into a secret place. Informal English = stash. Formal English = cache.
2. The act of collecting money by not spending it, or the money itself. English = saving, savings.
3. A collection of gold or silver objects, jewels or other valuable things, which has been hidden. English = treasure.
As a Verb or Adjective
1. To put something in a secret place, usually in order to keep it safe. English = hide, hide away, conceal. Informal English = stash. Idiomatic English = put out of sight, shut away. Formal English = secrete.
2. To put money away in a bank account or a secret hiding place. English = save.