Shiner

In land-based gambling, a shiner is an object with a reflective surface that is used for cheating. The cheater angles their shiner in such a way as to see the hidden cards of their opponents (e.g. a hole card in poker). In most cases, cheaters use thick chrome rings as shiners. Less commonly, a polished cufflink can be used.

The use of shiners is most common in small, informal gambling settings. Large, reputable gambling houses have robust anti-cheating surveillance systems that allow casino staff to quickly ban offending players and add them to the black book.

Shiner:

• a cheating device used for looking at other players’ cards