Parry, like evades is a method of dealing with damage before it actually connects to you (avoiding damage altogether rather than mitigating damage like AC or Absorb would do). The requirements for parry to work are as follows: You must be wielding a weapon that can parry (namely, a melee weapon with that specific flag), In order to parry something, the object attacking you must be also using a weapon that can be parried. As of 15.4.0.1 Patch on the Test Server, all Shadowlands mobs can be parried. Basically, the more points that you have into the skill Parry, the more likely you are to avoid taking any damage from an attack. It gives the same end result as when the attacker misses you. Parry is, in my opinion, a very useful skill and helps tremendously when tanking a melee damage mob.