Aiming can either be at a target, an adjacent room, or over a ledge.
AIMING AT A TARGET:
You can currently aim at other characters with suitable melee or ranged weapons. 'aim at ' and your character will focus on them with violent intent using their currently held weapon, or your current @default-htoh weapon if you are not wielding anything. You will react to various actions when doing this, such as intercepting them if they try to flee, or reacting violently if they try to get the jump on you. Aiming (and how effective it is) takes into account the relevant stats and skills of whatever weapon you choose to use to do it, as well as various stats and skills for reacting to the actions of your target.
AIMING AT ROOMS OR OVER LEDGES:
Using a ranged weapon, you are able to aim into other areas, with common sense dictating that weapons (or characters) with the proper equipment to aim that much farther, being able to do so. Once you're aiming at another room using this system ('aim at edge'(use the contracted direction name for this, sw instead of southwest, n instead of n, etc')), you can take your pick of targets and 'shoot with '. Make sure you're wielding your preferred ranged weapon when you do this, and take into account things that would impact your ability to make a clean shot. It will also take you a moment to confirm your shot and brace recoil, which depends on your relevant stats and skills.