Cheesey, you misspelled keister....which has an interesting word derivation.
1880–85; earlier, as underworld argot, handbag, suitcase, safe; of obscure origin, but words meaning “chest, box” are frequently adduced as sources, e.g., kist1, German Kiste, Yiddish kestl, etc. a box or chest, especially for sacred utensils.
In other words, at or near where the good stuff is kept be it a wallet or otherwise.
Originally Posted by: KRK