General alternatives:
* Civilian: This is the most common word and refers to someone who is not a member of the military.
* Non-military: This is a direct opposite and can be used in various contexts.
* Civil: This refers to matters related to citizens and their rights.
More specific alternatives:
* Commercial: This applies to businesses and activities not related to the military.
* Academic: This refers to things related to education and research.
* Political: This refers to activities related to government and governance.
Informal alternatives:
* Regular: This refers to someone who is not in the military.
* Non-combatant: This refers to someone who is not involved in fighting.
The best word to use will depend on the specific situation and what you are trying to convey.