Meaning

adjective applying to ordinary citizens as contrasted with the military

adjective not rude; marked by satisfactory (or especially minimal) adherence to social usages and sufficient but not noteworthy consideration for others; - W.S. Maugham

adjective of or occurring within the state or between or among citizens of the state

originFrom Middle English cyvyl, civil, borrowed from Old French civil, from Latin cīvīlis (“relating to a citizen”), from cīvis (“citizen”). Cognate with Old English hīwen (“household”), hīrǣden (“family”). More at hind; hird. (polite): Compare typologically urbane (<< Latin urbs), courteous (akin to court).

Etymology from Wiktionary, CC BY-SA 3.0