Attack of opportunity
From NWNWiki
An attack of opportunity (AoO) is a single extra melee attack that is automatically taken when an enemy makes themselves vulnerable, such as moving in combat (see also tumble or spring attack) or casting a spell.
[edit] Situations which provoke AoO
- drinking a potion
- casting a spell
- firing a ranged weapon in melee
- non-combat movement while in melee
- a disarm attempt (not improved disarm)
- fighting unarmed without the improved unarmed strike feat
[edit] Tip
Taking an AoO will cancel other actions, such as casting a spell. One way spellcasters avoid taking them is to carry a ranged weapon, since AoOs are only taken for melee weapons.
Some casters may find it beneficial to take the dodge, mobility, and spring attack feats in order to protect them from attacks of opportunity while they are positioning themselves in combat.
