Shiner is a term used by players or casino staff to refer to a tiny mirror or a small device used to reflect the light and reveal unexposed cards, such as the dealer’s hole card, for example.
Needless to say, a dealer’s hole card is hidden for a reason, and any attempt to catch a glimpse of it is regarded as cheating. If a player is caught using a shiner or any other device with a similar function, chances are they are going to be escorted out.
Depending on the casino’s policy and the severity of the accusations, players are most likely going to be stripped of their winnings. Furthermore, depending on the country’s or state’s laws, some players might even face criminal charges.
Therefore, make sure you don’t have any similar devices on you before you sit down at a casino table.