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"to conceal, hide," 1797, criminals' slang, of unknown origin, perhaps a blend of stow and cache. Related: Stashed; stashing.
"hoard, cache," 1914, from stash (v.). Slang sense of "personal supply of narcotics" is from 1942.
(also stash away) To hide; hoard; save up: I had not stashed any dough away/ I'd stash that jug (1797+)
[origin unknown; perhaps a blend of stow or store with cache]
A mustache; 'stache: He had a little red stash (1940+)