WordNet (r) 3.0 (2006):

stash
    n 1: a secret store of valuables or money [syn: hoard,
         cache, stash]
    v 1: save up as for future use [syn: hoard, stash, cache,
         lay away, hive up, squirrel away]

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "stash":
   asylum, bank, bolt-hole, bosom, bottle up, bundle away, bury,
   cache, coffer, conceal, concealment, corner, cover, covert,
   coverture, cranny, cubby, cubbyhole, dark corner, den, deposit,
   ditch, dugout, embosom, ensconce, file, file and forget, foxhole,
   funk hole, hide, hide away, hideaway, hideout, hidey hole, hiding,
   hiding place, hoard, hole, hutch, keep hidden, keep secret, lair,
   lay away, lay down, lay in, lay in store, lock up, lodge, niche,
   nook, pack away, plant, put away, recess, refuge, reposit,
   reservoir, retreat, salt away, salt down, sanctuary, screen,
   seal up, secret place, secrete, squirrel, store, store away, stow,
   stow away, stow down, undercovert, warehouse