From Unofficial Ansalon Wiki
Weapon skills are skills that allow you to master a particular weapon, the weapon skills available, level, and cost all very by class.
Action skills are skills which require you to input a command to use the skill, they can be a combat oriented skill or a skill that affects your current state.
Bash, Berserk, Dirt Kicking, Disarm, Engage, Kick, Rescue, Hunt, Lore, Sharpen, Track, Trip, Surge, Hide, Sneak, Peek, Blackjack, Backstab, Envenom, Deactivate, Pick Lock, Moon Phase, Detect Trap, Brew, Scribe
Passive skills are skills that do not require action from the player to use, once attained through leveling they are automatically in effect.
Combat Passive Skills
Combat passive skills are passive skills with primary combat focus.
Other Passive Skills
These passive skills do not directly relate to combat, rather they affect your character in other passive ways.
Language skills allow you to speak a particular language of Ansalon.
Skills broken down by class