A ball hog is a derisive term in basketball for a player who tends to handle the ball so exclusively that his behavior is damaging to his team. For this reason, "ball-hogging" is generally considered unacceptable playing behavior at all levels of basketball competition, especially by the player's teammates and coach. However, ball-hogging is not a violation of the rules of basketball.
The main behavior associated with being a ball hog is excessive shooting, including frequent attempts at difficult shots (especially when passing to an open player would've made the chances of a successful shot to the basket much greater). Ball hogs attempt to monopolize their play of the ball, frequently dribbling excessively and infrequently passing the ball to a teammate. The ball hog does this because of any combination of poor court vision, over-confidence in his own ability relative to that of his teammates, lack of confidence in his/her teammates' abilities, or sheer selfishness. Ball hogging tends to manifest itself statistically as an abnormally high percentage of team shot attempts by the ball hog and often low percentages of shot accuracy and assists. They also tend to have a very poor assist-to-turnover ratio (used as the main statistical indicator of how well a player "shares" the ball).
"Ball-hogging" can be detrimental to a team both immediately and in the long term. For instance, a player with ball-hogging tendencies may overlook or neglect a teammate who is open for a relatively easy shot, choosing instead to take a more difficult shot himself, often at the team's expense. Additionally, repeated ball-hogging by a player can damage a team's cohesiveness and alienate him or her from his teammates, coaches, and fans.