A Sniper is one of the two branches of the Explorer class. You must be land level 40 to become a Sniper.

The directory (Directory of Sniping) costs 16,000 gelt.

Specializing in Rifles/Shotguns, the sniper is well known as a Damage Dealer (DD) class. Able to cause a considerable amount of damage from a safe distance.
If done properly though, Sniper can be used as an AoE (Area of Effect) class. By using the skill "Frame Splash" (a lvl 43 skill).