Alter Aeon Online Help

Keywords are:  'skilllevel level thief_skill_level warrior_skill_level warr_skill_level warrskill thiefskill'

Some items may have one of the following effects:

Affects THIEF_SKILL_LEVEL by 1
Affects WARRIOR_SKILL_LEVEL by 1

These effects raise the level of your thief and warrior skills.  For
example, if you are a level 30 warrior wearing +5 WARRIOR_SKILL_LEVEL,
most of your skills will be used as though you were a level 35 warrior.