Noun

1. A person following the pursuits of civil life, especially one who is not an active member of the military, the police, or a belligerent group.

   Three civilians were apprehended by the soldiers and taken away in a military vehicle.

2. A person who does not belong to a particular group or engage in a particular activity.

Adjective

1. That which is not related to the military, police or other uniformed profession

   The three detainees were actually army defectors wearing civilian clothing.