Leaning or peeking is a feature in the Medal of Honor series. Unlike other FPS games, where, while aiming down the sights, one simply moves slower than normal, while aiming down the sights in a Medal of Honor game that allows for peeking, a player can look around or over cover to expose as little of themselves as possible, while still able to see and shoot the enemy. It is one of very few features in the Medal of Honor franchise that is available in more than two games, and it is almost exclusive to the series.
In Airborne and to an extent, European Assault, Leaning is more integrated and important than past games. This is because in the former, ironsights are only allowed while the player enters leaning mode.
In Medal of Honor (2010), leaning is featured in the singleplayer campaign, but is absent from the multiplayer. Lean is very handy when the player is playing on a high difficulty or Tier 1 Mode, as increased bullet damage can easily kill the player. Players can lean up 3 directions, to the left and right, and down 3 directions.
In Medal of Honor: Warfighter, peak and lean has been implemented in both the multiplayer and singleplayer. There are also 2 achievements/trophies related to using the Lean function. The first requires the use of Leaning to kill 1 enemy, the second requires 25 enemies killed while using Lean.