A Jinx is a type of curse that is believed to make their victims open to more bad luck, and is also believed to attract the attention of other people that are afflicted with a similar curse to its host.
It is also believed that a certain object can lead to a jinx, or bad luck, and it's also believed that tempting fate could lead to something being cursed, or jinxed. For example, suppose that you had a football team that you liked, and before their big game, you made a prediction that they were going to win the game.
Prediction would tempt fate, and it would cause bad luck to befall on the football team, and they may not win because of your prediction.
It is also recommended that you should never offer good luck to people like athletes, because it could also jinx the person into not doing well in their games.