Assassinate

Assassinate is a way to sneak up on a person and attempt to place your dagger
in his back, at exactly the point where it does most damage.  A successful
attempt will halve your opponent's health instantly. A good begin is half the
work done!
The chance of successfully assassinating a person depends on how well you
have practiced assassinate at your guild.

The classes that get the skill assassinate are:

thief      : Level  95 (good)
bard       : Level 106 (fair)
assassin   : Level  45 (excellent)
pirate     : Level  98 (fair)
rogue      : Level  67 (good)