Ability is any of the six natural traits that represent the basic definition of a player’s character. These scores are used to determine success or failure of many actions.
Strength measures a character’s muscle, endurance, and stamina. The probability of scoring a successful hit, the amount of damage done and the weight you can carry are all determined by strength. Every 2 points you add to strength, you gain +1 to hit and damage in melee combat. You can carry an additional 10 pounds of weight per point of strength.
Intelligence represents a character's memory, reasoning, and learning ability. Intelligence is what mana regeneration speed and how much extra mana you get when leveling up is based on.
Wisdom describes a composite of the character's willpower, common sense, and intuition. The higher the wisdom you character has, the more experience points you get for killing monsters and finishing quests. You get an extra 3% experience points gained for every point in wisdom.
Dexterity encompasses several physical attributes including hand-eye coordination, agility, reaction speed, reflexes, and balance. Dexterity affects how accurate ranged weapons are and armor class. Every two points of dexterity over 10, the character receives +1 to hit with ranged weapons and +1 to your armor class.
Constitution encompasses a characters physique, fitness, health, and physical resistance to hardship, injury, and disease. This ability affects the character's hit point total and how fast hit points (health) regenerates. High constitution is good for characters that do hand-to-hand melee.
Charisma measures a character's persuasiveness, personal magnetism, and physical attractiveness. It is important to all characters, but especially to those who must deal with non-player characters. Charisma lets you sell things for more and buy things for less. For every point above starting level in charisma, you get a 5% buy and sell bonus.