Camping
From Halopedia, the Halo wiki
Summary
Camping is the act of voluntarily keeping out of firefights by staying in one place while shooting from a distance or sneaking out from behind a corner to wreak havoc on an unsuspecting player passing by. Camping is rarely performed unless one has a powerful weapon such as the Sniper Rifle or the Energy Sword. Although camping is a legal and legitimate strategy, some players complain that it takes away from the inherent fun of the game.
A variant of camping known as "Spawn Rape" involves exploiting spawn points by camping near them and catching recently spawned players offguard and poorly-armed.