Thief. In fact it's a total mind boggle to me that a Thief or Thief like class was not in the game from the start. It's a basic class that every MMO has a variation off right off the bat.

The sad part about this is they may have made it so you can't have a Thief anymore as many of the jobs abilities were given to various other classes in XIV(such as mug on Pug and the trick attack like ability on Lancer or the flee like ability on ranger. On top of that daggers are already in the game and are for GLD so it's a wonder how they would make Thief work at all if they ever add it.)