speakeasy

noun

Etymology: Deverbal from speak easy (= speak quietly [interj.]); for the history, see Wikipedia at speakeasy § Etymology.

1. An illegal saloon or tavern, especially one operated during the American Prohibition period in the 1920s.

   “Many of the legitimate nightclubs of today sprang like legalized phoenixes from the still-hot ashes of the speakeasies of prohibition days.”

   “Retuning^([sic]) to Gotham, he came to intimately know Manhattan's speakeasy scene. “At a speakeasy,” Hirschfeld acknowledged, “you had to be known to get in...each place had its own clientele.” Membership cards, really fake IDs, were common.”