Lagswitching is deliberately causing the game to lag, which, due to how some games (like Destiny and the older Halo games) handle lag, gives you an advantage. The reason it's called "lagswitching" is because of an infamous video from years ago (like 2005-2006) that demonstrated how to hook up a router to a light switch, which, when flipped, would make the game lag. It can be hard to tell if someone is doing it or not, but possible signs include: -the game starting to lag when the enemy team is losing (someone on the losing team may be trying to turn it around) -the game lagging when encountering a specific player and no one else (they could be hitting their switch to make sure they kill you before you kill them) -the game goes into standby for your team and not the other (they could do this to take an objective or wipe your team without resistance)