In gambler parlance, and especially in sports gambling terminology, a square is simply an extremely inexperienced player, who is completely incapable of thinking outside the box, or of his “square.” Consequently, squares will typically lose money throughout the course of the season.
The most common mistakes squares make include having an inconsistent betting style, adjusting the wagers based on feelings and hunches, wagering at the last minute, neglecting the need to track statistics and keep their emotions in check and falling for gimmick bets which were designed to give the house a greater advantage.
Please note that while there is no specific, universal definition of a square, most people would agree that the majority of casual bettors who wager for leisure are squares. Experienced, profitable bettors – especially the ones that turned sports betting into their primary source of income – are often referred to as “sharps.”
“Bruce is such a square, he’s losing most of his bets. He should spend less time on browsing his online sports book and more time on improving his skills.”
The equivalent of a square in poker lingo would be a “donk” or a fish.