This feature has been removed from the game.
Melee was a category of skills. It included 1 hand blunt weapons, 1 hand edged weapons, piercing weapons, 2 handed blunt weapons, 2 handed edged weapons, melee energy weapons, deflect (then known as parry), sneak attack, multiple melee weapons, and fast attack.
The 18.7 patch removed the melee category. It renamed parry to deflect and placed it in a new body & defense category, placed 1 hand blunt, 1 hand edged, piercing, 2 handed blunt, 2 handed edged, melee energy, and multiple melee into a new melee weapons category, and sneak attack and fast attack into a new melee specials category.