The Collaborative International Dictionary of English v.0.48:

Offing \Off"ing\ ([o^]f"[i^]ng; 115), n. [From Off.]
   That part of the sea at a good distance from the shore, or
   where there is deep water and no need of a pilot; also,
   distance from the shore; as, the ship had ten miles offing;
   we saw a ship in the offing.
   [1913 Webster]

   in the offing
   (a) coming; arriving in the foreseeable future.
   (b) visible but not nearby.
       [PJC]

WordNet (r) 3.0 (2006):

offing
    n 1: the near or foreseeable future; "there was a wedding in the
         offing"
    2: the part of the sea that can be seen from the shore and is
       beyond the anchoring area; "there was a ship in the offing"