Etymology: Middle English of, from Old English — more at of
Date: before 12th century
(1) from a place or position <march off>; specifically away from land <ship stood off to sea> (2) at a distance in space or time <stood 10 paces off> <a long way off> b. from a course ; aside <turned off into a bypath>; specifically away from the wind c. into an unconscious state <dozed off> 2. a. so as to be separated from support <rolled to the edge of the table and off> or close contact <blew the lid off> <the handle came off> b. so as to be divided <surface marked off into squares> 3. a. to a state of discontinuance or suspension <shut off an engine> b. — used as an intensifier <drink off a glass> <finish it off> 4. in absence from or suspension of regular work or service <take time off for lunch> 5. offstage II. preposition Date: before 12th century 1. a. — used as a function word to indicate physical separation or distance from a position of rest, attachment, or union <take it off the table> <a path off the main walk> <a shop just off the main street> b. to seaward of <two miles off shore> 2. from the possession or charge of <had his wallet stolen off him> 3. — used as a function word to indicate the object of an action <borrowed a dollar off him> <dined off oysters> 4. a. — used as a function word to indicate the suspension of an occupation or activity <off duty> <off liquor> b. below the usual standard or level of <off his game> III. adjective Date: 1666 1. a. seaward b. right c. more removed or distant <the off side of the building> 2. a. started on the way <off on a spree> b. not taking place or staying in effect ; canceled <the deal was off> c. not operating d. not placed so as to permit operation 3. a. not corresponding to fact ; incorrect <off in his reckoning> b. poor, subnormal c. not entirely sane ; eccentric d. remote, slight <an off chance> 4. a. spent off duty <reading on his off days> b. marked by a periodic decline in activity or business <traveled in the off season for lower prices> 5. a. off-color b. inferior <off grade of oil>; also affected with putrefaction c. down <stocks were off> 6. circumstanced <worse off> IV. verb Date: 1717 intransitive verb to go away ; depart — used chiefly as an imperative <off, or I'll shoot> transitive verb slang kill, murder V. abbreviation office; officer; official
New Collegiate Dictionary. 2001.