Not much known about it …

It is believed to attempt to steal some items some npc or monsters are carrying.

Should immediately attempt to steal in the direction the player is facing.
Syntax : use_skill stealing

Readies the skill to be fired by the (default) keyboard key combination Shift+Arrow .
Should set the range attack into the foreground. See also the rotateshoottype command .
Syntax : ready_skill stealing

There are three functions in the server/server/skills.c code for stealing :

1. static int adj_stealchance (object *op, object *victim, int roll)
2. static int attempt_steal(object* op, object* who, object *skill)
3. int steal(object* op, int dir, object *skill)

1. looks very shifty
2. you feel itchy fingers getting at your pack.
3. Your pack feels strangely lighter.
4. Your %s is missing!
5. notices your attempted pilfering!
6. has nothing you can steal!
7. You can't steal from other players!
8. You can't steal from the dungeon master!
9. Your attempt is prevented!
10. But you have no free hands to steal with!