early 14c., "fact of holding or possessing;" mid-14c., "a being employed in something," also "a particular action," from Old French occupacion "pursuit, work, employment; occupancy, occupation" (12c.), from Latin occupationem (nominative occupatio) "a taking possession; business, employment," noun of action from past-participle stem of occupare (see occupy). Meaning "employment, business in which one engages" is late 14c. That of "condition of being held and ruled by troops of another country" is from 1940.
"a leisurely stroll, a ramble," 1828, from saunter (v.). Earlier it meant "idle occupation, diversion" (1728); "leisurely, careless way of walking" (1712).
"a professional person, one who follows a trade or occupation in a professional way," 1798, from professional (adj.).