Primary Attack is a term in Pillars of Eternity 2: Deadfire.
Many Abilities will state that they use either a Full or Primary Attack. When such Abilities are used, the character applies the effect through an attack with either all currently equipped weapons (Full Attack) or with their primary equipped weapon (Primary Attack).
This means that all of the statistics of the weapons still apply, including the damage and other effects that they provide.
Primary Attack Notes & Tips