Barred has the same meaning as banned, and it refers to someone who is not allowed to enter a brick-and-mortar casino. The term can also be used for any player who has had his IP address or account banned by an online casino.
There are many reasons why a player can get banned from a casino.
When it comes to land-based casinos, one of the main reasons is cheating, be it trying to defraud the casino or employ an illegal strategy. Furthermore, since casinos are often packed with people, some players can also be barred if they are acting inappropriately and negatively affecting everyone else.
When it comes to online casinos, the main reason why players get banned is that they refuse to comply with casinos’ terms and conditions — for example, trying to create an account while being underage or taking advantage of welcome bonuses.