"Civvie" is a slang term for a civilian or non-military person. There are several synonyms that can be used to replace "civvie," such as "non-combatant," "layperson," "ordinary citizen," "civilian," "non-militant," or "non-soldier." These words are often used in formal settings or in situations where a more respectful tone is necessary. In informal settings, "civvy" or "civ" is commonly used in place of "civvie." Regardless of which synonym is used, the key concept being conveyed is that the individual referred to is someone who is not involved in military activities or operations.