In the sport of association football, a defender is an outfield player whose primary role is to prevent the opposition from attacking.

There are four types of defender: 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 specialised for certain formations.

The job of the centre-back (also known as the centre-half, central defender, or stopper) is to stop opposing players, particularly the strikers, from scoring, and to bring the ball out from their penalty area. As their name suggests, they play in a central position.

In the modern game, most teams employ two centre-backs, stationed in front of the goalkeeper. There are two main defensive strategies used by centre-backs: the zonal defence, where each centre-back covers a specific area of the pitch; and man-to-man marking, where each centre-back has the job of covering a particular opposition player.

The sweeper is a more versatile type of centre-back who "sweeps up" the ball if an opponent manages to breach the defensive line. His position is rather more fluid than other defenders who man-mark their designated opponents. Because of this, the position is sometimes referred to as libero ([ˈlibero]; from the Italian word meaning "free", as used by the sports journalist Gianni Brera). Though the sweeper may be expected to build counter-attacking moves, and as such requires better ball control and passing ability than a typical centre-back, his talents are often confined to the defensive realm. For example, the catenaccio system of play, used in Italian football in the 1960s, employed a purely defensive sweeper who only "roamed" around the back line.

A defender is usually a participant in defense (military) or defense (sports).

Defender(s) or The Defender(s) may refer to:

Football refers to a number of sports that involve, to varying degrees, kicking a ball with the foot to score a goal. The most popular of these sports worldwide is association football, more commonly known as just "football" or "soccer". Unqualified, the word football applies to whichever form of football is the most popular in the regional context in which the word appears, including association football, as well as American football, Australian rules football, Canadian football, Gaelic football, rugby league, rugby union and other related games. These variations of football are known as football "codes".

Various forms of "football" can be identified in history, often as popular peasant games. Contemporary codes of football can be traced back to the codification of these games at English public schools in the eighteenth and nineteenth century. The influence and power of the British Empire allowed these rules of football to spread, including to areas of British influence outside of the directly controlled Empire, though by the end of the nineteenth century, distinct regional codes were already developing: Gaelic Football, for example, deliberately incorporated the rules of local traditional football games in order to maintain their heritage. In 1888, The Football League was founded in England, becoming the first of many professional football competitions. In the twentieth century, the various codes of football have become amongst the most popular team sports in the world.

Vincent Jean Mpoy Kompany (born 10 April 1986 in Uccle, Brussels) is a Belgian footballer who plays for Manchester City and the Belgium national team. He is capable of playing at both centre back and defensive midfield. In the 2011–12 season he was awarded the captaincy of Manchester City, leading his club to win the Premier League that season, their first league title in 44 years.

Kompany began his professional career at Anderlecht, spending three years at the Belgian club before moving to German club Hamburger SV in 2006. In the summer of 2008, at the age of 22, he completed a transfer to his current club, Premier League side Manchester City. He has since established himself as an integral part of the Manchester City squad and is one of the bargain buys of the revolutionised City era, blossoming into one of the Premier League's best centre backs. Kompany was included in the Premier League Team of the Year for two years in a row in 2011 and 2012, and won the Premier League Player of the Season in 2012.

Daniel Alves da Silva (born 6 May 1983), commonly known as Dani Alves, is a Brazilian footballer. He plays as an attacking right defender for FC Barcelona and the Brazilian national team.

Before joining Barcelona, Alves spent a successful six year spell with Sevilla FC, winning two UEFA Cups and the Copa del Rey with the Andalusian side. He joined Barcelona for €32.5m, becoming the most expensive defender to date. Alves won the Treble in his first season with the club and a further Spanish super cup, European super cup, and FIFA Club World Cup, thus achieving the Sextuple. Also, he helped the club to clinch another Spanish super cup, two league titles, and a UEFA Champions League in the years that followed. Alves has held a Spanish passport since 2005. On Thursday, September 29, 2011, Alves was appointed as a Special Olympics Ambassador for its Global Football program, charged with promoting respect and inclusion in football for people with intellectual disabilities, particularly in the run up to the 2014 FIFA World Cup.