gaff, n.³ 1. [early 19C+] in concrete senses, a cheating device in gambling (or in any crooked form of sideshow), orig. a small hook set in a ring used by a card-sharp. 2. [1920s+] a fraud, a racket. 3. [1940s] the place – a fake ‘bookmaker’s’ or ‘stockbroker’s office’ – in which a confidence trick is carried out. 4. [1940s–50s] in pl., crooked dice. 5. [1940s–60s] in fig. use of sense 1, a gimmick, a hidden trick.