Aggro

Aggro is a slang term meaning "to cause hostile NPC mobs to attack by getting too close to them." Short for "Aggravate". The Compass displays a white transparent circle, the Danger Zone, that surrounds your character. Any mob (indicated by red dots) that even slightly enters the Danger Zone (often called "aggro bubble" or "aggro circle") immediately becomes aware of your presence and is aggravated, causing it to attack you. Careful understanding and awareness of your Danger Zone is very important, especially if your teammates are low on health/energy or already attacking another group of enemies. A target "breaks aggro" when it disengages and stops attacking, although it may still be in the Danger Zone when this happens. Several things can cause an enemies to break aggro including using AoE skills such as Fire Storm or running away and activating a running skill like Sprint.