A civilian under international humanitarian law's a person who isn't a member of his or her country's armed forces. The term's also often used colloquially to refer to people who aren't members of a particular profession or occupation, especially by law enforcement agencies, which often use rank structures similar to those of military units. The International Committee of the Red Cross 1958 Commentary on IV Geneva Convention Relative to the Protection of Civilian Persons in Time of War Article… (More on Civilian)