What is Audacity, exactly? Well, put simply, it's a PvMP stat that will provide players with benefits such as reducing incoming damage and lowering the duration of crowd control abilities. Higher audacity, obviously, equates to lower incoming damage and shorter crowd control effects. But why introduce this feature in the first place? According to the post, the team believes that having PvMP and PvE gear on the same progression path resulted in underwhelming or overly difficult-to-obtain PvMP gear since the team had to ensure that "the PvMP items did not devalue the PvE offerings." In addition, Turbine feels that, thanks to the damage changes made in Rise of Isengard, PvMP combat was too fast-paced. The addition of audacity is intended to nix both of these problems.
Freeps will acquire their first rank of Audacity automatically at level 40, and further ranks will be boosted by PvMP gear that can only be purchased with commendations. Creeps, meanwhile, will gain their first rank of Audacity upon creation, and they'll gain further ranks by purchasing them directly from class trainers (seeing as how Creeps don't wear equipment).
For the full details on this new system, just click on through the link below to the official dev diary.