A parry often made while closing distance with the intent of using the hilt to stop the attacking weapon.
Japanning
A process of coating with black paint usually decorated with gold or coloured paint.
Joining of the blades
To engage weapons. Not common practice until the mid seventeenth century.
Joining
The action of engaging in combat.
Jour
An opening into which an attack may be launched.
Judge 
An official in the sport of fencing whose duty is to see hits and signal the president immediately when he has seen one.
Jump
Evasive upward action avoiding a strike to the legs.
Jump backward
Evasive action of removing the body out of the line of attack be leaping backwards, while still facing ones opponent.
Jump forward
Rapid advance where footwork is exaggerated to gain more ground. Quite literally jumping forward.
Jury
The president and judges who officiate at a fencing event.