nonmilitary; civilian
Used to describe things not related to the military, such as organizations, zones, or activities.
The area was designated a demilitarized zone.
Space development for nonmilitary purposes is advancing.
非武装 specifically means 'unarmed' or 'demilitarized' in a physical sense, while 非軍事 is broader, covering any nonmilitary aspect.
Compound of 非 (hi, 'non-') and 軍事 (gunji, 'military affairs').