The Collaborative International Dictionary of English v.0.48:

Bogey \Bo"gey\, n.; pl. Bogeys. [Also bogie and bogy,
   plural bogies.]
   1. A goblin; a bugbear.

   Syn: bogeyman.
        [Webster 1913 Suppl.]

              I have become a sort of bogey -- a kill-joy. --Wm.
                                                  Black.
        [Webster 1913 Suppl.]

   2. (Golf) a score one stroke over par for a hole; formerly,
      the definition of bogey was the same as that now used for
      par, i.e., an ideal score or number of strokes, for each
      hole, against which players compete; -- it was said to be
      so called because assumed to be the score of an imaginary
      first-rate player called Colonel Bogey. Now the standard
      score is called par.
      [Webster 1913 Suppl. +PJC]

   3. (Mil.) an unidentified aircraft; in combat situations,
      such craft not identified as friendly are assumed to be
      hostile.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Bogy \Bo"gy\, n.; pl. Bogies. [See Bogle.]
   A specter; a hobgoblin; a bugbear. "Death's heads and
   bogies." --J. H. Newman. [Written also bogey.]
   [1913 Webster]

         There are plenty of such foolish attempts at playing
         bogy in the history of savages.          --C. Kingsley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bogy
    n 1: an unidentified (and possibly enemy) aircraft [syn: bogy,
         bogie, bogey]
    2: an evil spirit [syn: bogey, bogy, bogie]