From WoWWiki
Targets of melee attacks can have a chance to parry each incoming frontal attack. A successful parry nullifies the attack (for the attacker it's like a miss), and reduces the swing timer of the defender. It is a passive ability which does not require any action to be used. Most melee classes get this ability - warriors at level 6, hunters and paladins at level 8, and rogues at level 12. Shamans have a 20 point Enhancement talent (Spirit Weapons) which grants them the parry ability in addition to threat reduction on their melee attacks.
Functionality
- If a character or mob has a parry chance, it's always active and can take effect on every incoming frontal melee attack
- If applicable, the parry chance is added to the attackers attack table
- The only stat which increases the chance to parry is defense (0.04% per point)
- Some classes can increase their chance to parry with talents (either direct or via defense)
- Similarly items can directly increase the chance to parry or indirectly via defense
- Attacks from the rear cannot be parried. Mobs sometimes do so anyways - this can be due to a bug or because they turn very quickly in place.
- After a succesful parry, the defenders swing timer is reduced (or even reset), resulting in an increased damage output (for details see Formulas:Parry). While tanks like to profit from this effect, melee damage dealers should attack from behind whenever possible.
See also
