A double bogey is when you shoot 2 over par on a hole in golf, meaning +2 gets added to your score.
To understand what a double bogey is in golf, you must first understand what par is. Par is a preset number of shots on every hole that dictates what a player's score on that hole would be. For example, if a hole is a par 3, and a player makes it into the hole in 3 shots, then no points will be added or subtracted from their score. If they make it in 2 shots, then 1 point will be taken away from their score, known as a birdie. Similarly, if a player makes it in 4 shots, then 1 point will be added to their score, known as a bogey. Remember, the goal of golf is to have the lowest score possible.
A double bogey is when you make a shot in 2 extra strokes then the par of the hole. An example of this would be taking 5 shots on a par 3, resulting in +2 being added to your score. Double bogeys are huge mistakes that a golfer can make, and can be devastating. You want to make as few shots as possible on every hole to minimize your score. The player with the lowest score wins, and double bogeys certainly won't help you win.