early 14c., "inhabitant of a city," from Anglo-French citezein (spelling subsequently altered, probably by influence of denizen), from Old French citeien "city-dweller, town-dweller, citizen" (12c., Modern French citoyen), from cite (see city) + -ain (see -ian). Replaced Old English burhsittend and ceasterware. Sense of "inhabitant of a country" is late 14c. Citizen's arrest recorded from 1941; citizen's band (radio) from 1947. Citizen of the world (late 15c.) translates Greek kosmopolites.
A person of a more conservative, established, and prosaic caste than oneself; square (1960s+ Black & counterculture)