A fork of Rural Dictionary
In the context of the 2009 game Call of Duty: Modern Warfare 2, it refers to the style of gameplay associated with the use of the Marathon, Lightweight, and Commando perks (hence the acronym). Using them in conjunction gives you maximum mobility. Marathon lets you sprint endlessly, lightweight increases overall movement speed, and commando allows you to knife players from a great distance. Often used in conjunction with a tactical knife attachment for pistols, which roughly doubles/triples the speed at which you knife. Some players object to the use of this, since it focuses on knifing rather than the core gunplay. Lag also favors the MLC user because they can potentially enter a room and knife someone before they show up on the victim's TV set (see how to kill a camper). MLC users are also frustrating to shoot at because they are such fast-moving targets. Haters gonna hate. In their defense, this is a very unsafe and wreckless form of gameplay, requiring you to charge head first at people with guns in an attempt to knife them. Kudos to anyone who actually does well using only his knife. A very similar style of gameplay switches out pistol with tactical knife and commando, for a shotgun and steady aim (which makes hip-firing more accurate).
I was playing Modern Warfare 2 when some guy using MLC knifed me. My jimmies were rustled but I got over it and kept playing.