Any player on the defense who is guarding against the receivers on an offensive passing play. Pass defenders can play one of two styles: man-to-man, where a defender is responsible for a single player for the duration of the play, and zone, where a defender is responsible for a particular area of the field and guards any individuals entering their particular zone.
Pass defenders play the important role of keeping passes from being completed downfield by the quarterback. Each pass defender wants to deflect the ball away from the receiver or, if possible, to intercept the ball by catching it themselves. The two different styles of pass defense are man-to-man and zone. Man-to-man relies on athleticism and instincts since a player is solely responsible for their player, and must outrun them to the ball. Zone is a team based defense that relies on communication and teamwork. This is because the entire pass defense is operating as a unit rather than a series of individuals. Offensive players will be passed off from one defender to another as they enter and exit the various defensive zones. Most modern defenses use a combination of the two: certain players will guard the receivers man-to-man while others will help out in various regions of the field.