"The relative angle that a weapon will move horizontally or vertically when fired. Sustained fire will increase recoil over time. A lower recoil value means the weapon will move less between fire."
Recoil is one of the stats in Blacklight: Retribution that affect how your weapon performs. Through the history of the game, it has been changed several times, last with patch 1.000. Before this, Recoil was a regular number value, now it is an angle, much like the different types of Spread.