Civilian
From Halopedia, the Halo wiki
A Civilian, according to international humanitarian law, is a person who is not a member of his or her countries armed forces. The term is also often used colloquially to refer to people who are not members of a particular profession or occupation, especially by law enforcement agencies, which often use rank structures similar to those of military units. Often, the military's main purpose and occupation is to defend the civilians from invaders. However, many civilians, such as Dr. Hasley are involved with the military. So far, extremely few have been seen in any of the three games, except for the factory workers, and the garb, appearance or personality of any alien civilian is never divulged.