In the sport of association football, a defender is an outfield player whose primary roles is to stop attacks during the game and prevent the opposing team from scoring goals.

Centre backs are usually are in pairs, with 2 full-backs to their left and right, but can come in threes with no full backs

There are four types of defenders: centre-back, sweeper, full-back, and wing-back. The centre-back and full-back positions are essential in most modern formations. The sweeper and wing-back roles are more specialized for certain formations.