Alter Aeon Online Help

Keywords are:  'thief skill peek'

Skill: peek                     Lvl 19 Thie  (42%)
                                (obscure)   Requires: case
                                Group: Thief stealing skill group

Usage:
peek <character name>

This is a mid-level thief skill similar to case, allowing a thief to
discover what a potential target might be carrying in various pouches or
containers.  Advanced thieves typically use this skill to make sure a
victim is carrying sufficient loot to be worth stealing from.