late 14c., "judge or authority on civil law," from noun use of Old French civilien "of the civil law," created from Latin civilis "relating to a citizen, relating to public life, befitting a citizen; popular, affable, courteous," alternative adjectival derivative of civis "townsman" (see city). Sense of "non-military and non-clerical person, one whose pursuits are those of civilian life" is attested by 1766. As an adjective, "pertaining to or characteristic of a civilian," from 1640s.
