Deep: describes the positioning of a player (or a line of players, such as the defence or midfield) who is playing closer to their own goal than they traditionally would. A defence may drop deep against a team with fast attacking players, to reduce the amount of space behind the defence for fast-paced players to break into.[91] Attacking players or midfielders who traditionally play deep may be described as being a deep-lying forward or a deep-lying playmaker.

Reference: 1)https://en.wikipedia.org/wiki/Glossary_of_association_footba...