If you like to get up close and personal with your enemies without the weight of heavy armor clanking around your skin, the thief profession should be of interest to you. It focuses on quick strikes, stealth, and the art of theft. It's a perennial PVP powerhouse, but can also contribute massive amounts of melee damage in groups or solo play. The thief is unique among the classes in that most of their weapons only have two skills associated with them; the third skill on your toolbar will vary based on the combination of main-hand and off-hand weapon. Their stealth also makes them deadly opponents. There are many skills that enable a thief to enter the shadows, becoming untargetable and unattackable except by AOE skills. While in stealth, you'll also obtain a new skill on your skillbar, which varies based on the type of weapon that you have equipped.
The primary thief mechanic is the art of stealing, which will allow you to nab a weapon or other item from your targeted opponent and use it for yourself. The first press of the F1 key will initiate the steal, after which pressing F1 again will use the item that you stole and enable you to use Steal again, assuming the cooldown has run out. The effect of the item will depend on what you're attacking; if you steal from a ghost, you might be able to use Consume Ectoplasm (ew!) to gain all available boons for a short period of time, while stealing from a plant-based enemy might let you use Branch Bash, dealing damage and launching them backwards. There are a lot of stealable effects, so experiment and see which one you pull down!
Also, you'll note that the area above your skill bar is taken over by your initiative meter. Thief weapon skills have no cooldown, instead relying on an expenditure of initiative (which rapidly refills) to be used. The more powerful the skill, the more initiative that you expend, and the longer you'll have to wait before you can use that skill again. This enables a thief to unload a large amount of burst damage in a short period of time, but can also leave you somewhat defenseless if you get caught by an opponent without enough initiative to escape or counterattack.
As a thief, enjoy the mesmerizing wonder of the Steal Recharge Rate increase, available on a trait bar near you! The Steal skill has a lengthy 45 second cooldown, but if you invest here, you'll be able to cut that down considerably.