Source : Webster's Revised Unabridged Dictionary (1913)

Off \Off\, adv. [OE. of, orig. the same word as R. of, prep.,
   AS. of, adv. & prep. [root]194. See {Of}.]
   In a general sense, denoting from or away from; as:

   1. Denoting distance or separation; as, the house is a mile
      off.

   2. Denoting the action of removing or separating; separation;
      as, to take off the hat or cloak; to cut off, to pare off,
      to clip off, to peel off, to tear off, to march off, to
      fly off, and the like.

   3. Denoting a leaving, abandonment, departure, abatement,
      interruption, or remission; as, the fever goes off; the
      pain goes off; the game is off; all bets are off.

   4. Denoting a different direction; not on or towards: away;
      as, to look off.

   5. Denoting opposition or negation. [Obs.]

            The questions no way touch upon puritanism, either
            off or on.                            --Bp.
                                                  Sanderson.

   {From off}, off from; off. ``A live coal . . . taken with the
      tongs from off the altar.'' --Is. vi. 6.

   {Off and on}.
      (a) Not constantly; not regularly; now and then;
          occasionally.
      (b) (Naut.) On different tacks, now toward, and now away
          from, the land.

   {To be off}.
      (a) To depart; to escape; as, he was off without a
          moment's warning.
      (b) To be abandoned, as an agreement or purpose; as, the
          bet was declared to be off. [Colloq.]

   {To come off}, {To cut off}, {To fall off}, {To go off}, etc.
      See under {Come}, {Cut}, {Fall}, {Go}, etc.

   {To get off}.
      (a) To utter; to discharge; as, to get off a joke.
      (b) To go away; to escape; as, to get off easily from a
          trial. [Colloq.]

   {To take off}, to mimic or personate.

Source : WordNet®

off and on
     adv : not regularly; "they phone each other off and on" [syn: {on
           and off}]