Cadet Apprentices, or Cadet Apps, are recruits who have shown themselves capable of handling themselves in the military. This is usually a first mission reward, and shows that the person with this rank is smart enough to complete their job with efficiency. Other than being a mark of professional prowess, this rank gives a character 100 DA a week.
For a full listing of Nepleslian military ranks, see Ranks of the Star Military of Nepleslia.