Aggressive

Aggressive (often abbreviated as aggro) is a term used to describe something (typically a mob) that will attack without provocation.

Aggressive Mobs
Aggressive mobs will initiate combat with the player. This is as opposed to a passive mob which will only attack if attacked first. Mobs can have different levels of aggression, which determine how quickly (or if) they will attack.

Types
Following are the types of aggro mobs from least aggressive to aggressive on sight.

Dispel aggro
Mobs of this kind will attack if you attempt to cast dispel magic on them. Note however that if they have magic resistance and your dispel fails utterly, they will not retaliate.

Sleep aggro
Mobs of this kind will attack if you lower your guard by sleeping. Resting will not trigger them to attack, however.

Memory aggro
Some mobs will remember that you fought with them and will attack you if they meet you again. This is often indicated with the phrase "X recognizes you as murderer!" Other mobs are able to spread the word that you attacked them, which can cause an entire city of mobs to recognize and attack you in the worst of cases.

Solace aggro
These mobs can attack even if you have a peace or solace spell affecting the room. They usually can usually do this via a spec.

Charisma aggro
Charisma aggro mobs attack if your charisma is lower than some value defined by the creator of the mob. The presence spell can be useful avoiding combat with mobs of this type.

Alignment aggro
These mobs will attack only players who are of a specific alignment, for example an evil monster might attack only neutral or good characters.

Absolutely aggro
These mobs will attack you no matter what unless you make an effort to avoid detection or prevent mob aggression in the room with solace or peace.

Consider
will sometimes tell you if a mob is aggro or not with the message "X would not hesitate to come after you."

Aggro Area
An area that contains a high number of aggressive mobs. As a result, these areas are generally harder but tend to grant more experience.