Compartmentalization is keeping information and processes within your mind segregated, especially in ways that keep knowledge possessed by some of your reasoning processes being accessed by other processes.
From an alternative angle, one can think of compartmentalizing one's different activities or domains from each other. when one couple the skills or habits from one to another, e.g., the religious scientist who does not apply scientific thinking outside the lab.
One might even have excellent epistemological performance in one domain and terrible performance in others.