Alter Aeon Online Help

Keywords are:  'thief skill stealthy movement'

Skill: stealthy movement        Lvl 22 Thie  (28%)
                                (critical)   Requires: hide and sneak
                                Group: Thief stealth skills

Usage:
sneak <direction>

When using the stealthy movement skill, you will try to sneak and stay
hidden as you move in the specified direction.  If you are following
another player, you will automatically try to use this skill if you
are hidden, and if you have sneak enabled.

Moving stealthily can be a time consuming experience however - be prepared
to wait if you have to do so, or are with others that are using the skill.