Guile is a skill used in the art of stealth. Each level of guile comes with new abilities and potential risks. Keep in mind many of these actions may be considered illegal in a town, and guards will react with violence to subdue you immediately if you are caught or fail in front of them.
Available at the first level of guile. An attempt at learning what was said in a private conversation from one person to another. If you fail, everyone will know you tried to listen in. If you are successful, you will be able to hear their gossip. Whether the information will be fruitful or not is never guaranteed. You can only attempt to listen to whispers that occurred up to four hours ago, and can only attempt to listen to the whisper of a particular speaker once per hour.
% chance = 10 + random 1-10 + (dexterity * 6) + (guile * 10)
Available at the second level of guile. The less obvious attempt at opening a lock which would otherwise be unavailable to you. This project can only be started with a lockpick, and can only be progressed by a single person. Completion of the project will give you an unlocked door/vehicle/building, and access to what is within, without leaving evidence that the lock was meddled with other than remaining unlocked. Lockpicking takes half the total effort a crowbar takes. For reference, it takes a full 12 hours with a single person working at top guile. Lockpicking a door does not produce an event on the room that is being picked.
Available at the third level of guile. This allows you to do two things:
attempt to look at a person's inventory and, if successful, have the option to try and take an item from that inventory unnoticed.
If you are successful, you will gain the item and then the inventory will no longer be available to you; you'll have to try again if you want more. You can only attempt to take one item at a time (yes this includes coins), but you cannot take an item equipped or worn by the victim. This is a risky action, and if you fail, all around you will know of your attempt, and it may induce enforcement from guards. It's important to note though that law breaks only count for actually taking items, not for looking. Whether you fail or not, your access to their inventory will be revoked once an attempt to take an item is made. Risk of being caught is calculated with the weight of the item you are taking, as well at the victim's dexterity versus your own. Being able to view someone's inventory will only last for 12 hours, and you can only try to pickpocket someone once per hour. Victims who you are attempting to steal from too soon won't give you the option. You cannot try to pickpocket items that have a weight of 40 or more.
Peeking: 100 - (50 + (victim dexterity * 12) - (12 * thief guile)) = % chance of thief success
Taking: ((thief guile/20 +0.75)((6- victim dexterity)/20 + 0.75)((40- item weight)/40) * 100)
If calculated weight is < 0 then the result is 0.
Final result is a rounded integer used a percentage chance of success.