Weapons come in various sizes and lengths. It just depends on the class that can use it. These are just the weapon styles. The actual name of the weapon is up to the owner.
Normal
Swords: Used by Soldier, Knight, Warrior, Swordsman, and Paladin.
Axes: Used by Warrior, Swordsman, Barbarian, Berserker, and Titan.
Standard Bow: Used by Warrior, Swordsman, Archer, and Sniper.
Long Bow: Used by Sniper. (Longer range than the bow.)
Dagger: Used by Swordsman, Knife Thrower, Thief, Rogue, and Assassin.
Staff/Spear: Used by Knight, Soldier, Warrior, Swordsman, Sage, Druid, Elder, and Lore Student.
Mace: Used by Swordsman, Warrior, Paladin, Barbarian, Berserker, and Titan.
Unique
All unique weapons are used only by the Unique Specialist.
Whip: The whip is a dance style weapon.
Scythe: Used as a "Death Necromancy" weapon. (Reaper style.)
Tonfa/Elbow Blades: Very fast weapons. Attack style is unknown.
Nunchucks: Normally use by monks and people who do not wish to kill their apponent.