Accuracy determines how likely a creature is to hit its opponents with basic attacks and spells. More specifically, it applies to melee attacks and most AoE spells and abilities. Ranged attacks and “skill-shot” spells, instead, always hit the opponent if they're aimed correctly. It is contrasted by the target’s Fortitude, Evasion and Willpower modifiers, depending on the type of attack. Accuracy is determined by a creature’s Perception.
Base Accuracy vary on creature type.