Can someone explain what this means

Expertise reduces the change that your target will parry or dodge, making it exceptional for both tanks and mele dps.

its pretty easy to cap on this stat mabye 1~2 peices of gear with 25 or so should do it till sun well and its the kind ot thing where anyone who ever plans to melee a boss should get it for tanks its an additional 10% chance to hit and the reduction in parries means less parry induced thrashings from a reset swing timer