Source : Webster's Revised Unabridged Dictionary (1913)

Skittish \Skit"tish\, a. [See {Skit}, v. t.]
   1. Easily frightened; timorous; shy; untrustworthy; as, a
      skittish colt. ``A restiff, skittish jade.'' --L'Estrange.

   2. Wanton; restive; freakish; volatile; changeable; fickle.
      ``Skittish Fortune's hall.'' --Shak. -- {Skit"tish*ly},
      adv. -- {Skit"tish*ness}, n.

Source : WordNet®

skittish
     adj : unpredictably excitable (especially of horses) [syn: {spooky},
            {nervous}]